Fisher English Training Part 2 Speech represents the second half of a collection of
conversational telephone speech (CTS) that was created at the LDC
during 2003. It contains 5,849 audio files, each one containing a full
conversation of up to ten minutes. Additional information regarding
the speakers involved, and types of telephones used, can be found in
the companion text corpus of transcripts, Fisher English Training Part 2, Transcripts (LDC2005T19).
The Fisher telephone conversation collection protocol was created
at LDC to address a critical need of developers trying to build robust
automatic speech recognition (ASR) systems. Previous collection
protocols, such as CALLFRIEND and Switchboard-II and the resulting
corpora, have been adapted for ASR research but were in fact developed
for language and speaker identification respectively. Although the
CALLHOME protocol and corpora were developed to support ASR
technology, they feature small numbers of speakers making telephone
calls of relatively long duration with narrow vocabulary across the
collection. CALLHOME conversations are challengingly natural and
intimate. Under the Fisher protocol, a very large number of
participants each make a few calls of short duration speaking to other
participants, whom they typically do not know, about assigned
topics. This maximizes inter-speaker variation and vocabulary breadth
although it also increases formality.
Previous protocols such as CALLHOME, CALLFRIEND and Switchboard
relied upon participant activity to drive the collection. Fisher is
unique in being platform driven rather than participant
driven. Participants who wish to initiate a call may do so; however
the collection platform initiates the majority of calls. Participants
need only answer their phones at the times they specified when
registering for the study.
To encourage a broad range of vocabulary, Fisher participants are
asked to speak on an assigned topic which is selected at random from a
list, which changes every 24 hours and which is assigned to all
subjects paired on that day. Some topics are inherited or refined from
previous Switchboard studies while others were developed specifically
for the Fisher protocol.
The first half of the collection (Fisher English Training Speech
Part 1) was released by the LDC in 2004 (LDC2004S13 for speech data,
LDC2004T19 for transcripts). Taken as a whole, the two parts comprise
11,699 recorded telephone conversations.
The individual audio files are presented in NIST SPHERE format, and
contain two-channel mu-law sample data; "shorten" compression has been
applied to all files.
Data collection and transcription were sponsored by DARPA and the
U.S. Department of Defense, as part of the EARS project for research
and development in automatic speech recognition.
For an example of this corpus, please examine this audio sample.
© 2003-2005 Trustees of the University of Pennsylvania