Note: This document describes the transcription methods and
conventions as employed by the Meeting Transcription team. Because
the transcripts were later reformatted to conform to the new MRT
specification, an ADDENDUM is provided at the end of the document,
detailing how the markings described here were modified. Consult the
ADDENDUM for the forms the user should expect to see in the MRT files.
We intend to provide tools to convert between the two conventions.
======================================================================
The ICSI Meetings Corpus: Transcription Methods
Jane Edwards, ICSI
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0. Overview.
The Meetings Corpus transcripts are word-level transcripts,
time-synchronized to digitized audio recordings.
The meetings were recorded with close-talking and far-field
microphones. The transcripts were based mostly on the close-talking
microphones, either separately or blended together in a so-called
"mixed" channel.
When listened to separately, the close-talking microphones enabled
detection of quiet events, and disentangling of utterances during
overlaps. The mixture of close-talking microphones made it possible to
to follow the flow of the conversation and hear utterances in context,
with much better audio quality than would have been possible from
far-field microphones. Far-field microphones were used either when a
speaker was not wearing a microphone (e.g., during meeting set-up), or
when a microphone malfunctioned.
Transcripts were prepared by means of the "Channeltrans" interface
(http://www.icsi.berkeley.edu/Speech/mr/channeltrans.html).
Channeltrans is an extension of the "Transcriber" interface (Barras,
Geoffrois, Wu, and Liberman, 2000), modified by David Gelbart and Dan
Ellis to accommodate multiple speakers, and overlapping speech.
Both Transcriber and Channeltrans preserve events and time bins
in which they occurred, and both of them do so in XML format.
Channeltrans differs from Transcriber in that it preserves the channel
number in addition to the time and event. Whereas Transcriber has only
one display ribbon for speaker utterances, Channeltrans affords as
many display ribbons as there are speakers. Furthermore, Channeltrans
allows the time bins on each ribbon to be totally independent of
those on all other ribbons. Both properties -- multiple ribbons and
independent time segmentation -- were essential for the Meetings
Corpus data, due to the large number of participants and great amount
of overlapping speech in these meetings.
The basic strategy of the transcript was to view each ribbon as
capturing the actions of a particular meeting participant, heard over
the close-talking microphone which he or she was wearing. The person
wearing a particular microphone is called the "dominant" speaker on
that channel. In cases of crosstalk, other speakers may be heard on
the same channel, but only the events produced by the dominant speaker
are transcribed on the display ribbon corresponding to that channel.
Expressed another way, no event is transcribed more than once, or
attributed to any channel other than the channel on which the speaker
is the dominant speaker.
The most basic unit of analysis in these transcripts is an event, the
time bin containing it, and the person who produced it. The time bins
are only practical units rather than theory-relevant units. The goal
was simply to have units of manageable size with no truncated words.
Thus, an utterance can extend into subsequent time bins, so long as
there are clean breaks between them.
To speed the transcription process, a speech-nonspeech detector was
used to provide a preliminary segmentation of the data into time
bins. Although the time bin boundaries were not always accurate, it
was still more efficient than having transcribers add all boundaries
themselves. This process is explained in greater detail in section 3
below.
After the transcripts were completed, they were checked, first by
other transcribers, and then by one of two senior researchers. The
details of the checking procedures are described in section 4 below.
After the transcripts were completed and checked, some of the
surface labels below were converted by scripts into XML tags (see
Addendum). It's important to note that this is a difference only of
the surface-level graphemes; not the distinctions which are encoded
in the transcripts. This difference has been expressed elsewhere
as one of "markup" versus content (see Edwards, 1995, p. 20). The
distinctions described below are the meanings captured in the Meetings
Corpus, regardless of which surface graphemes are used to display them
in the markup.
This document describes the specific content distinctions which were
encoded in the transcripts. Section 1 describes the transcription
conventions which were used for all interactional parts of the
meetings (i.e., all but the Digits task). Section 2 indicates how
these conventions were applied to the Digits task. Section 3 presents
the details of implementing the transcription conventions, esp. with
reference to Channeltrans and the speech-nonspeech presegmenter.
Finally, Section 4 describes the steps and processes used in checking
the transcripts before considering the transcription encoding phase
complete.
1. Transcription Conventions (except for the Digits task, which is
discussed in section 2)
The transcription conventions used in this project were shaped by two
sets of factors. The first set was the intended audience: primarily
speech recognition research, and secondarily linguistic and discourse
research. The former audience requires matching of word forms against
lexical entries. The latter requires preserving communicative events.
The second set of factors were practical considerations: speed
of data entry, robustness against human error, and computational
utility. These interests are shared by all well-designed transcription
systems. Some of the strategies used include: minimalism (using as
few separate symbols and as few interpretive decisions as possible),
use of familiar literary conventions where possible (e.g., a dash for
incompletion), use of conventions which are reasonably transparent
through other motivations where that's not possible, etc. (See
Edwards, 2002 for a more comprehensive list).
The focus of the transcripts was on capturing the flow of audible
events, especially the words which were spoken, and who spoke them.
The basic unit of analysis was an event, the time bin in which it was
located, and where relevant or possible, which participant produced
it.
There are five types of "events" in these transcripts:
1) Words
2) Utterances
3) Vocalizations which are not words - e.g., laughs, coughs, breaths
4) Nonvocalized sounds - e.g., door slams, microphone noises, chair squeaks
5) Silence
With words, utterances and other vocalizations, it was almost always
possible to determine the relevant actor by comparing loudness across
different close-talking microphones, or by noticing distinctive
characteristics of voice or accent.
Non-vocalized sounds, such as doors slamming or chairs squeaking, were
attributed to individuals in the transcripts when this was obvious
from context or from comments from participants (e.g., when someone's
microphone suddenly becomes active, or when someone teases the person
for being late). Where it was not clear who produced them, the noises
were simply noted as occurring, without attribution.
Silence was the absence of events of the other four types. Some
speakers were silent for long stretches during a meeting. This type of
silence was routinely encoded.
When a silence occurred within an utterance it was sometimes encoded
but not exhaustively so, and similarly, for when breath occurred
within an utterance.
In addition to the five event types, the transcripts contain
additional clarifying information or "metacomments," typically
expressed inside curly brackets with a "QUAL" label inside the opening
bracket. These comments include such things as contextual notes, and
observations concerning acoustic or discourse features.
The transcripts also contain some types of information which can
be derived indirectly from the representation rather than being
explicitly encoded. A primary example of this is overlapping events,
which can be defined with reference to time tags on two different
speaker channels.
Sections 1.1 through 1.5 provide details of the five event types.
Section 1.6 explains the encoding of metacomments. Section 1.7
discusses the relative exhaustiveness of encoding of the various types
of distinctions in the discourse section of the meetings.
1.1. Words
All word-level transcription followed the same rules:
- encode words in standard orthography,
- indicate uncertainty of transcription where it exists.
Under no circumstances was "word salad" allowed, i.e., transcribing a
string of words which sounds somewhat like the speaker's utterance,
but which was most certainly wrong or made no sense in context.
Where uncertainty arose, parentheses were used, and one of the
following encodings was used inside the parentheses:
- If the transcriber was reasonably sure of a word or phrase (and
it made sense in context), the uncertain word or phrase was
enclosed in parentheses: (word or phrase)
- If the transcriber was not sure of a word or phrase, but was
fairly certain that it was n syllables long, the number of
syllables was followed by an "x": (nx)
- If the stretch of speech was totally undecipherable and
contained an indeterminate number of syllables: (??)
There are several types of "words" in the transcripts:
a. Standard word forms found in the dictionary.
These are encoded in standard orthography. Hyphens are used to
bind together the parts of a lexical compound, as in standard
orthography. Hyphens are also used to bind together components of
some frequently occurring technical terms (e.g., speech-nonspeech
detector).
b. Truncated words. These are words whose articulation is stopped by
the speaker before they are completed. This is encoded by means of
a hyphen appended to the end of whatever was articulated.
For example:
th-
c. Numbers, decimals and percentages. These are spelled out in standard
orthography (e.g., "five point two", "twenty-five").
d. Pronounceable acronyms (e.g., "UNESCO", "ChiLDES") are encoded
with the same capitalization patterns as are usually used for them
in writing.
e. Spoken letters are encoded as capital letters followed by underscores (_).
When they occur individually there is an underscore after each spoken
letter.
- discussion points:
"So the news for me is A_, my forthcoming travel plans in two weeks."
- variable names: "the log of X_ plus N_"
"That might, you know, give us additional input to belief A_ versus B_."
When they occur in clusters, there is an underscore (and no space) after
each letter except the last one:
- acronyms pronounced as a string of letters: "I_C_S_I"
(Acronyms which are pronounced as words rather than strings of
letters are encoded with no underscores, e.g., "ICSI" when pronounced
like "icksy".)
- spellings: "His name is Hudson, H_U_D_S_O_N."
When they are a part of a technical term, there is always an
underscore after the letter. The separate parts of the term are
bound together by the underscore alone or by an underscore plus a
hyphen or by a hyphen, depending on whether the letter precedes or
follows the non-letter part of the term, or, when there are two
letters, depending on what would seem the most easily readable
encoding:
- technical terms:
- letter followed by non-letter segment:
"This is a plot of C_zero, the energy."
- non-letter segment followed by letter:
"What you're saying is we have a Where-X_ question."
- two letters and a non-letter segment: "M_-three-L_ enhancement"
In this corpus, underscores occur only in the context of spoken letters.
f. Word forms typical of spoken discourse, which may be absent from
a dictionary (e.g., reduced forms such as "gonna" and "cuz",
backchannels such as "mm-hmm", interjections such as "oops!"),
but which often have a conventionalized spelling in literature.
These are encoded using the shortest list of forms which capture
meaning differences but avoid needless proliferation. (For example,
"uh-huh" is always encoded as "uh-huh"; if it is lengthened, the
lengthening is treated as being an embellishment and is handled by
a comment immediately following the word or utterance.)
g. "Vocal gestures". These are less word-like vocalizations which, however,
are communicative (rather than being reflexive behavior). For
example, "pppt!" which is sometimes used to signal an easy task,
or "hhh" which stands for a vocalized outbreath of frustration or
difficulty.
h. Departures from canonical pronunciation: the "PRN" tag. This category
was motivated by the goal of advancing speech recognition research,
to indicate pronunciations which are noticeably different from
the pronunciation variants which would normally be expected of
the speaker who uttered it. PRN items are recognizable by humans,
but are perceived by human transcribers as being beyond the range
of normal pronunciation variation, such that non-humans could be
expected to find them more difficult to recognize than usual.
Items which are tagged PRNs include:
- words which have been extremely lengthened (i.e., seeming subjectively
to be probably several standard deviations beyond normal length for
that speaker)
- words which contain rare acoustic artifacts which might affect the
waveforms (e.g., an initial vocal squeak, or a crack in the voice)
- non-words which arise from speech errors of some types but which
sound prosodically complete
Items which are NOT tagged as PRNs:
- prosodically incomplete words/nonwords (already handled via the
truncation convention above, using the end-hyphen)
- words which are tinged by a non-native speaker's mother tongue
(since these pronunciations would be part of an accurate model
of that person's variety of English). That is, if the person is
a native Spanish speaker and says what sounds like "Espain" instead
of "Spain", the word is simply transcribed as "Spain" without special
marking.
The following is an example of PRN marking:
'O_K. {PRN "mm-kay"}
PRN marking has these parts:
- an apostrophe (') pre-pended to the beginning of the non-canonical
stretch (which may be one or more words in length),
- the word(s) in the non-canonical stretch, spelled in standard
orthography,
(O_K).
- a PRN tag after the stretch, and
- an optional rendering of the speaker's pronunciation,
or a description of how it is different from canonical pronunciation
(in this example, "mm-kay").
The following illustrate some other types of PRN marking:
'folks. {PRN "folksss"}
'She {PRN lengthened}
'this could {PRN "thisss kid"}
The description field is usually empty for speech errors because
they are accidental productions which should not normally be viewed
as intended renderings of a word in the language (and hence would
not be normally added to a model).
Lengthening (and other embellishments) which are within the normal
range of pronunciation variation are normally noted in QUAL comments
(discussed later in this document) instead of PRN comments.
i. Foreign words and phrases.
These are encoded in a manner similar to non-canonical
pronunciations (section h), except with a language abbreviation
in place of "PRN" (e.g., GER for German). A recognizer trained
on English would not be expected to have them in its lexicon or
language model. Tagging them makes it possible to exclude them from
some experiments if desired.
'ist fertig. {GER "is finished"}
'oder {GER "or"}
'Nein! {GER}
'cum grano salis. {LATIN meaning "with a grain of salt"}
'en passant, {FRENCH "in passing"}
'Bien sur {FRENCH meaning "of course"}
'pero {SPAN meaning "but"}
'tango de la muerte. {SPAN}
1.2. Utterances
A discourse consists of units of various sizes. For purposes of this
document, "utterances" are stretches of words which begin with a
capital letter and end with a punctuation mark and/or a comment in
curly brackets.
Punctuation marks signal two types of information: whether an utterance is
complete or not and what type of utterance it is:
- Exclamations end with exclamation point (!).
- Statements end with a period (.) unless they are intended as questions.
- Utterances with the pragmatic force of questions end with a question mark
(?). (This includes some statements spoken with rising intonation, but
not explanations spoken with rising intonation, in which case, the
rising intonation serves to elicit listener feedback, rather than to
signal a propositional question.)
- Disfluencies and incomplete utterances end with a space and a hyphen unless
their last word is truncated, in which case they end with simply the
hyphen attached to the truncated word (section 1.1.b).
The following example contains only completed words:
I was - these meetings - I'm sure someone thought of this, but these -
This example has a truncated word (and thus has a hyphen appended to it):
It'd be nice, but - but I - I - I do- I don't wanna count on it.
If the utterance was clearly a question, the hyphen can be followed by
a space and a question mark (- ?). For example:
So, uh, what was the date there? Monday or - ?
The "- ?" notation is used only when there is no doubt that the utterance
was intended by the speaker as a question (e.g., due to a combination of
syntactic factors, prosody, response from seeming addressee, etc.).
Only very few truncated utterances are marked as being truncated questions
in the interests of staying close to the actual data rather than guessing
what the person might have intended or said if he or she had continued
speaking.
The end-punctuation marks in this corpus were based considerably less
on prosodic distinctions than is true of many discourse corpora.
This approach was chosen with the intention of providing the primary
audience (speech researchers) with the types of distinctions of
greatest use to their research.
Some prosodic information is preserved by two other mechanisms:
- asterisk (*) for marking prosodic prominence:
"So it's not really - you're not really *exposed to German very much."
- QUAL comments for describing various properties of the utterance which
precedes the comment:
"We use a generalization of the - the SPHERE format. {QUAL rising intonation}"
This particular utterance was a statement of clarification by the
speaker, with rising intonation to get feedback from the listener.
The utterance would have had a very different meaning (and been
pragmatically bizarre in the context in which it arose) if it had been
encoded as a syntactic question, i.e., punctuated with a question
mark.
Neither stress nor intonation is exhaustively coded in the corpus.
They are added mainly as points of enticement for future work.
Other punctuation in this corpus:
- comma (,), used in a manner similar to written orthographic standards,
- double quotation mark ("), used to encode any material which is being
quoted by the speaker.
The literary convention of encoding embedded quotes in single quotes
(') is avoided to avoid confusions with PRN items. (See section 1.1
above.) Instead, embedded quotations are marked by double quotation
marks (") as are un-embedded quotations. This can give rise to some
rare ambiguities of scope, where it is not clear where the embedded
quote ends within a quoted stretch. But there are only a handful of
cases in the entire corpus which have embedded quotes, so it was not
considered an abundant enough event to require an extra convention.
It is illegal to have a space in front of the following markers:
period, comma, exclamation point, utterance-final quotation marks.
It is illegal to have a space immediately after this marker: asterisk.
The ordering of punctuation marks is roughly that of standard
orthography, with one exception: commas and periods can be placed
outside of the final double quotation mark if it is notionally
justified, for example, if the speaker is quoting a term within an
utterance.
Thus:
The term to use there is "temporary".
Colons and semicolons are not allowed in the corpus. If an utterance
would most naturally be rendered with a colon in written orthography,
a comment containing the word "colon" is sometimes put immediately at
that point in the utterance (to enable a shift in conventions later on
if that distinction becomes important to preserve).
1.3. Vocalizations other than words
When the speaker is not speaking, he or she sometimes produces other
vocal sounds, including such things as "laugh", "cough", "breath",
etc. These are set apart from the utterance, and tagged as so-called
"VOC" events. They are enclosed in curly brackets after an initial
"VOC" tag.
When a laugh or cough, etc. occurs *during* the articulation of a
word, it is viewed not as a VOC, but rather as a modification of
on-going articulation, and is instead tagged as a "QUAL" (i.e.,
"qualification" comment) event.
(QUALs are described in a later section, below.)
There are far too many types of VOCs to discuss them all separately,
but a couple of them warrant some comments.
The VOC descriptors "laugh-breath" or "breath-laugh" were intended
initially to signal an event which was ambiguous between a laugh
and a breath. It has become generalized to also capture some events
which are clearly laughs but lack voicing, such as events which are
identifiable from quick rhythmic breathiness and context.
The VOCs "inbreath" and "outbreath" are more specific than "breath"
but these distinctions are not exhaustively encoded.
If two VOC events occur in succession, they are generally mentioned in
separate bracketed comments (to keep the list of VOCs as short
as possible).
1.4. Nonvocalized sounds
These include "door slam", "microphone noise", "chair squeaks", etc.
They are enclosed in curly brackets after an initial "NVC" tag.
Many of them are audible across more than one channel.
Some of them are attributable to individual speakers but many are not.
If two NVC events occur in succession, they are generally mentioned in
separate bracketed comments (to keep the list of NVCs as short
as possible).
1.5. Silence
Double periods without space between them (..) means silence.
1.6. Clarifying information
There are several types of clarifying information in the corpus.
1) punctuation (discussed in section 1.2 above)
2) metacomments expressed in curly brackets with an explicit tag indicating
the type of information they encode.
Two types of metacomments were discussed in section 1.1 above:
those for non-canonical pronunciations (PRN) and those for non-English
expressions (GER, etc.).
The main type of metacomment in the data is the QUAL comment.
It is used for comments concerning such things as likely referent, likely
addressee, or various possibly interesting discourse factors such as
voice quality. It is also used to note modifications of articulation
(e.g., lengthening) or to capture simultaneity of events
("during microphone spike" or "while laughing"), and so forth.
Speaker identifiers may appear in comments which indicate the intended
addressee for an utterance or which clarify ambiguous references or
describe ongoing actions, but these are relatively rare. The primary
mechanism for attributing acts to individual participants is the XML
"channel" tags.
In the original transcripts, QUAL comments were encoded in curly brackets
beginning with a "QUAL" tag.
All QUAL comments are positioned either at the point of relevance or
immediately after the segment or unit to which they apply most clearly;
not before it.
In the event of an interrupted utterance, the PRN precedes the space and
hyphen, whereas the QUAL follows it. The reason for this is a difference
of scope for their most typical instantiations.
That is, PRN is usually word-level in what it clarifies (and less often
applies to phrases) whereas QUAL is usually phrase level (and less often
applies to individual words).
The contents of a QUAL were kept as short as possible, and were kept
to as short a list as possible by using the same wording across
meetings as much as possible. Thus, "again" was avoided on subsequent
occurrence of an event. QUALs containing multiple parts were split into
two adjacent comments where this would lead to a shorter total list of
them in the corpus (i.e., avoiding compounding in the same way as discussed
for VOCs and NVCs above).
1.6.1. The scope of clarifying information
Comments which refer to a word or utterance are placed immediately
after the word or utterance they refer to, and in the same time bin.
For example:
It's mine! All mine! {QUAL while laughing}
The comment refers to all or part of the preceding utterance.
In the interests of time, the exact scope was usually not specified,
though sometimes it was:
which I'm not gonna have time to do in the next few
days, {QUAL last 5 words spoken while laughing}
The goal was to indicate the occurrence of something interesting
in a time bin in the most efficient and least time-consuming way.
In some cases, a comment contains background information which may be
relevant not only to the preceding utterance but also to utterances
which follow it. For example:
Speaker B:
I was just gonna say maybe fifteen minutes later would help me
a little bit just cuz I have a class up at Dwinelle b- just
before this. That's why I was a little late today because -
Speaker A:
*Wow. You did really *well. {QUAL addressee recently had knee surgery}
Speaker B:
Thanks. {VOC laugh} Well, I took the bus for part of the way.
But um, that might help me just a *little bit because then it -
I - you know, I'm gonna - gonna be hobbling a little slowly.
It is often impossible to determine the point at which such a state of
the world becomes relevant or irrelevant to the unfolding interaction.
For this reason, in the present conventions, as in most discourse
transcription conventions, it is desirable to insert comments where
they are known to be relevant but to avoid giving an explicit end-point
to their relevance to the discourse, as this is ultimately unknowable,
often even to the participants themselves.
(See Edwards, 1993, pp. 17-18 for contrasting approaches to scope.)
1.7. Exhaustiveness of the encoding
It's useful to mention the priorities of transcription for this project,
as a guide to what phenomena were most robustly and exhaustively encoded.
The most robust parts of the corpus are:
- "words" in the technical sense of strings of one or more characters
representing phonations by the speaker. This includes all
of the categories and subcategories of section 1.1.
- speaker attribution for the words. That is, correctly attributing
articulations to the person who actually uttered them rather than
to another speaker.
- encoding of communicatively salient vocal (VOC) events - esp. "laugh"
- encoding of loud reflexive VOC events - esp. "cough", "sneeze",
and to a lesser degree (because these were less audible, and easier
to overlook) "sniff"
- encoding of loud nonvocal (NVC) events - esp. door slams
- encoding of certain types of QUAL comments - esp. "while laughing"
because it is the most common speech embellishment in the data,
because it is communicatively significant, and because it
may hinder word recognition by human and machine.
Reasonably robust but somewhat less exhaustive/consistent:
- events which occurred too often to be exhaustively marked within
the parameters of this project: microphone spikes, breaths.
Some meetings contain more exhaustive encoding of breaths than others.
- events which were less audible (lower volume): some backchannels
or sniffs. Many of these were overlooked entirely by the automatic
presegmenter and were added manually by transcribers or by
data checkers. It is inevitable that some were overlooked, esp.
the unusual category of backchannels which were of such low volume
that they were not even audible to others at the meeting.
- the punctuation at the ends of utterances.
The goal was to provide a useful and reasonably consistent set of
markers, and this was accomplished. Punctuation was double-checked
or even triple-checked by different transcribers, but there is more
chance of variability in this part of the corpus than in the parts
noted above.
Sporadically encoded curiosities for future work:
This third category contains a variety of phenomena which caught
the transcribers' or data checkers' attention as interesting and
worth preserving, but which were not part of the main goals of
the project. This includes: rare events, curiosities and ideal examples
of particular phenomena. "Rare events" are such things as
extremely long silence across all channels (as in Bro005):
{QUAL very long silence, 11 seconds}
Under "curiosities", there are glottal clicks, and unusually
high whistles produced by a talented linguist in Bsr001.
Under "ideal examples" is the remarkably tight rhythmic coordination
of backchannels across 5 speakers at several points in Btr002.
These and similar things were encoded in the corpus to provide a
sense of the richness of the data and a glimpse of what other types
of phenomena a person might study in this corpus which go beyond
the scope of basic transcription.
2. Conventions used for the Digits task
The "Digits" task involved reading strings of one or more digits from
lines of printed scripts. Not every meeting contained this task,
but where it occurred, they were transcribed as follows:
- Every event was transcribed: from the reading of the digit-script
number through the last digit of the last digit string on that
person's page, including occasional phrases such as
"Sorry, I'll start again."
- The "{DGTS}" tag was put at the end of every non-empty time bin.
- All numbers were written as words (rather than Arabic numerals).
- Each digit string was isolated to a time bin by itself (rather
than being split across time bins or combined with other strings)
to the extent this was possible to determine.
- If the scripted string contained clusters of digits, commas were
often used to indicate the separation of the clusters of digits in
that string.
Occasionally utterance-final punctuation marks and initial capitalization
were used in the transcription of the Digits task, but these should be
regarded as being only very approximate. The digit strings themselves are not
syntactic units (and hence can't be categorized as "declarative", etc.).
In addition, since they were being read and were not meaningful,
their intonation contours are not the same as spontaneous discourse.
3. Implementation of the corpus conventions
The transcripts involved two tasks: encoding events and the boundaries
of the time bins which contained them. The location of time tags was
driven mainly by a simply practical goal of keeping the units to a
manageable size while at the same time not truncating any words.
Because the meetings were often large, it was impractical to accomplish
this in a strictly manual way (i.e., having transcribers do all the
segmentation into time bins). In an hour meeting with nine
participants, for example, it would have taken nine hours to listen to
each channel exhaustively to find the time bins which required
encoding. Viewing the energy waveform for activity might seem an
effective solution, but in fact, it was not very reliable.
A highly effective approach turned out to be to apply a speech-nonspeech
detector to the audio recordings to generate a preliminary segmentation
into time bins to be adjusted later by human transcribers. (For
details see Pfau, Ellis & Stolcke, 2001).
Transcribers were encouraged to correct, adjust, or add new
segmentations as needed. The time bins were intended simply as
units of a manageable size with clean breaks on either side (i.e.,
no truncated words). Utterances may be contained in a single time
bin or they might extend across several time bins. The time bins
were not intended as definable discourse units or prosodic units
but simply as manageable units.
The ICSI transcribers were students in liberal arts (all but one in
linguistics). They were chosen for perceptiveness and overall
attentiveness to linguistic detail.
4. Steps and processes of checking the transcripts for word-level accuracy
After a transcript was completed, it was checked for spelling errors,
and then assigned to a different student transcriber for checking. The
second transcriber reviewed it in its entirety while listening to the
audio recording. After this was completed, the process was repeated by
one of two senior researchers.
The "read-throughs" were extremely time consuming but were invaluable
for word-level accuracy. In addition, they led to the detection of
many backchannels which had been overlooked by the presegmenters and
the first transcriber.
More mechanical checking was also used, such as standard spell checking
and scanning exhaustive listings of forms for words which seem implausible
(and then checking them in context to be sure). These checks
were useful in detecting blatant errors and increasing uniformity of
word-level encoding across meetings and transcribers.
In a number of cases, there were words or phrases which were
acoustically strong but remained incomprehensible even to
senior researchers. In these cases, the actual speakers were asked
to listen and demystify them.
Once checking was completed by a senior researcher, the transcripts
were checked in a final way: by being made available for correction
and approval by the participants themselves. Although very few errors
were detected in this way, those which were were gratefully accepted
and fixed.
REFERENCES
Barras, C., Geoffrois, E., Wu, Z. and Liberman, M. (2000).
Transcriber: development and use of a tool for assisting speech
corpora production. Speech Communication special issue on Speech
Annotation and Corpus Tools, Vol 33, No 1-2.
Edwards, Jane A. (1993) Principles and contrasting systems of transcription.
In J.A. Edwards and M.D. Lampert (eds). Talking data: Transcription and
coding in discourse research. Lawrence Erlbaum Associates, Inc.:
Hillsdale, NJ. (pp. 3-31).
Edwards, Jane A. (1995) Principles and alternative systems in the
transcription, coding and mark-up of spoken discourse.
In G. Leech, G. Myers, and J. Thomas (eds). Spoken English
on Computer: Transcription, Mark-up, and Application.
NY: Longman Publishing.
Edwards, Jane A. (2002) "The Transcription of Discourse." In
D. Tannen, D. Schiffrin, and H. Hamilton (eds). The Handbook of
Discourse Analysis. NY: Blackwell (pp. 321-348).
Pfau, T., Ellis, D.P.W. and Stolcke, A. (2001),
Multispeaker Speech Activity Detection for the ICSI Meeting Recorder.
Proc. IEEE Automatic Speech Recognition and Understanding Workshop,
Madonna di Campiglio, Italy.
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ADDENDUM: Conversion to MRT format
Many of the categories of mark-up described above (VOC, NVC, QUAL, PRN, ...)
were reformatted for the MRT files. Here we provide an itemization of
several such classes and the mappings applied to them.
... original ................ becomes ................. MRT form ...
uncertainty: (words) words
uncertainty: (nx) @@
uncertainty: (??) @@
pronunciation: 'word {PRN descriptn} word
where the description is optional
non-English: 'words {LANG comment} words
where FL = de (German), es (Spanish),
fr (French), it (Italian), la (Latin)
and the comment is optional
emphasis: *word word
vocal sound: {VOC sound}
nonvocal sound: {NVC sound}
short pause: ..
long silence (between turns) not explicitly encoded; rather inferred from absence of time bins containing non-silence events
comment: {QUAL comment}
Digits task: {DGTS}
also the tag includes the
attribute: DigitTask="true"
note: This conversion occasionally resulted in unusual formatting.
For example, '*' was sometimes used to denote word-internal emphasis,
such as "P_L_*P", which mapped to "P_L_ P ",
so caution should be exercised when suppresssing < ... > markings.
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