Fisher English Training Part 2, Speech

Fisher English Training Part 2, Speech was developed by the Linguistic Data Consortium (LDC) and contains 975 hours of English conversational telephone speech (CTS). It contains 5,849 audio files, each one containing a full conversation of up to 10 minutes. The corresponding transcripts for these speech files are available in Fisher English Training Part 2, Transcripts (LDC2005T19), which includes additional information regarding the speakers involved, and types of telephones used. These two corpora represent the second half of a CTS collection that was created at LDC during 2003. The first half of the collection, released in 2004, comprises Fisher English Training Speech Part 1 Speech (LDC2004S13) and Fisher English Training Speech Part 1 Transcripts (LDC2004T19). Taken as a whole, the two parts contain 11,699 recorded telephone conversations totaling approximately 1,960 hours. 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. The Fisher protocol uses a large number of participants, and each one converses with another participant, whom they typically do not know, for a short period of time to discuss the assigned topics. This maximizes inter-speaker variation and vocabulary breadth while also increasing formality. Previous protocols such as CALLHOME, CALLFRIEND, and Switchboard relied on 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 randomly selected from a list, which changes every 24 hours and 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.