File: readme.doc, updated 10/12/90 The DARPA TIMIT Acoustic-Phonetic Continuous Speech Corpus (TIMIT) Training and Test Data NIST Speech Disc CD1-1.1The TIMIT corpus of read speech has been designed to provide speech data forthe acquisition of acoustic-phonetic knowledge and for the development andevaluation of automatic speech recognition systems. TIMIT has resulted fromthe joint efforts of several sites under sponsorship from the Defense AdvancedResearch Projects Agency - Information Science and Technology Office(DARPA-ISTO). Text corpus design was a joint effort among the MassachusettsInstitute of Technology (MIT), Stanford Research Institute (SRI), and TexasInstruments (TI). The speech was recorded at TI, transcribed at MIT, and hasbeen maintained, verified, and prepared for CD-ROM production by the NationalInstitute of Standards and Technology (NIST). This file contains a briefdescription of the TIMIT Speech Corpus. Additional information including thereferenced material and some relevant reprints of articles may be found in theprinted documentation which is also available from NTIS (NTIS# PB91-100354).1. Corpus Speaker Distribution-- ---------------------------TIMIT contains a total of 6300 sentences, 10 sentences spoken by each of 630speakers from 8 major dialect regions of the United States. Table 1 shows thenumber of speakers for the 8 dialect regions, broken down by sex. Thepercentages are given in parentheses. A speaker's dialect region is thegeographical area of the U.S. where they lived during their childhood years.The geographical areas correspond with recognized dialect regions in U.S.(Language Files, Ohio State University Linguistics Dept., 1982), with theexception of the Western region (dr7) in which dialect boundaries are notknown with any confidence and dialect region 8 where the speakers moved arounda lot during their childhood. Table 1: Dialect distribution of speakers Dialect Region(dr) #Male #Female Total ---------- --------- --------- ---------- 1 31 (63%) 18 (27%) 49 (8%) 2 71 (70%) 31 (30%) 102 (16%) 3 79 (67%) 23 (23%) 102 (16%) 4 69 (69%) 31 (31%) 100 (16%) 5 62 (63%) 36 (37%) 98 (16%) 6 30 (65%) 16 (35%) 46 (7%) 7 74 (74%) 26 (26%) 100 (16%) 8 22 (67%) 11 (33%) 33 (5%) ------ --------- --------- ---------- 8 438 (70%) 192 (30%) 630 (100%)The dialect regions are: dr1: New England dr2: Northern dr3: North Midlanddr4: South Midland dr5: Southern dr6: New York City dr7: Western dr8: Army Brat (moved around)2. Corpus Text Material -- --------------------The text material in the TIMIT prompts (found in the file "prompts.doc")consists of 2 dialect "shibboleth" sentences designed at SRI, 450phonetically-compact sentences designed at MIT, and 1890 phonetically-diversesentences selected at TI. The dialect sentences (the SA sentences) were meantto expose the dialectal variants of the speakers and were read by all 630speakers. The phonetically-compact sentences were designed to provide a goodcoverage of pairs of phones, with extra occurrences of phonetic contextsthought to be either difficult or of particular interest. Each speaker read 5of these sentences (the SX sentences) and each text was spoken by 7 differentspeakers. The phonetically-diverse sentences (the SI sentences) were selectedfrom existing text sources - the Brown Corpus (Kuchera and Francis, 1967) andthe Playwrights Dialog (Hultzen, et al., 1964) - so as to add diversity insentence types and phonetic contexts. The selection criteria maximized thevariety of allophonic contexts found in the texts. Each speaker read 3 ofthese sentences, with each sentence being read only by a single speaker.Table 2 summarizes the speech material in TIMIT. Table 2: TIMIT speech material Sentence Type #Sentences #Speakers Total #Sentences/Speaker ------------- ---------- --------- ----- ------------------ Dialect (SA) 2 630 1260 2 Compact (SX) 450 7 3150 5 Diverse (SI) 1890 1 1890 3 ------------- ---------- --------- ----- ---------------- Total 2342 6300 103. Suggested Training/Test Subdivision-- -----------------------------------The speech material has been subdivided into portions for training andtesting. The criteria for the subdivision is described in the file"testset.doc". THIS SUBDIVISION HAS NO RELATION TO THE DATA DISTRIBUTED ONTHE PROTOTYPE VERSION OF THE CDROM.Core Test Set:The test data has a core portion containing 24 speakers, 2 male and 1 femalefrom each dialect region. The core test speakers are shown in Table 3. Eachspeaker read a different set of SX sentences. Thus the core test materialcontains 192 sentences, 5 SX and 3 SI for each speaker, each having a distincttext prompt. Table 3: The core test set of 24 speakers Dialect Male Female------- ------ ------ 1 DAB0, WBT0 ELC0 2 TAS1, WEW0 PAS0 3 JMP0, LNT0 PKT0 4 LLL0, TLS0 JLM0 5 BPM0, KLT0 NLP0 6 CMJ0, JDH0 MGD0 7 GRT0, NJM0 DHC0 8 JLN0, PAM0 MLD0 Complete Test Set:A more extensive test set was obtained by including the sentences from allspeakers that read any of the SX texts included in the core test set. Indoing so, no sentence text appears in both the training and test sets. Thiscomplete test set contains a total of 168 speakers and 1344 utterances,accounting for about 27% of the total speech material. The resulting dialectdistribution of the 168 speaker test set is given in Table 4. The completetest material contains 624 distinct texts. Table 4: Dialect distribution for complete test set Dialect #Male #Female Total ------- ----- ------- ----- 1 7 4 11 2 18 8 26 3 23 3 26 4 16 16 32 5 17 11 28 6 8 3 11 7 15
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