The texts and speakers in TIMIT have been subdivided into suggested training and test sets using the following criteria:
NOTE: THIS TEXT SUBDIVISION HAS NO CORRESPONDENCE WITH THE ORIGINAL TRAINING MATERIAL DISTRIBUTED ON THE PROTOTYPE CD-ROM. Use only the designated training material on this disc for training purposes.
Core Test Set
Using the above criteria, 2 male speakers and 1 female speaker from each dialect were selected, providing a core test set of 24 speakers. Each speaker read a different set of 5 SX sentences. Since each SI sentence was read by only one speaker, these texts did not impose constraints in selecting the texts or speakers.
The selected texts were checked to ensure that the set included at least one occurrence of each phoneme. The phonemic analysis was based on concatenated phonemic transcriptions of the words in the sentence, not the actual, realized phonetic transcription. Thus, the phonetic allophones found in the test data may be expected to differ from the underlying phonemic forms in accordance with typical phonological variations.
The core test set thus contains 192 different texts ((5 SX + 3 SI sentences) x 24 speakers). To avoid overlap with the training material the 2 SA sentences have been excluded from the core and complete test sets. THESE SENTENCES ARE INCLUDED ON THE CD-ROM, BUT SHOULD NOT BE USED FOR TRAINING OR TEST PURPOSES.
Table 1 lists the speakers in the core test set for each dialect. This set is the minimum recommended set for test purposes.
Table 1: Speakers in the Core Test Set Dialect Male Female #Texts/Speaker #Total Texts ------- --------- ------ -------------- ------------ 1 DAB0, WBT0 ELC0 8 24 2 TAS1, WEW0 PAS0 8 24 3 JMP0, LNT0 PKT0 8 24 4 LLL0, TLS0 JLM0 8 24 5 BPM0, KLT0 NLP0 8 24 6 CMJ0, JDH0 MGD0 8 24 7 GRT0, NJM0 DHC0 8 24 8 JLN0, PAM0 MLD0 8 24 ----- ---------- ------- ------ Total 16 8 192Complete Test Set
The complete test set is obtained by including all of the speakers that said any of the texts read by any speaker in the core test set. In doing so, it is insured that no sentence text appears in both the training and test material. Thus, since each SX text was read by a total of 7 speakers, an additional 6 speakers for each text are included, giving a total of 168 speakers. The 168 speakers represent 27% of the total number of speakers. The resulting dialect distribution of the 168 speaker test set is given in Table 2.
Table 2: Dialect Distribution of Speakers in 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 8 23 8 8 3 11 ------- ----- ------- ------ Total 112 56 168The complete test set consists of a total of 1344 sentences, 8 sentences from each of the 168 speakers. In this set there are 120 distinct SX texts and 504 different SI texts. Thus, roughly 27% (624) of the texts have been reserved for the test material.
The minimum recommended test material is the core test set, which consists of 2 male speakers and 1 female speaker from each dialect and 192 unique texts. Those wishing to perform more extensive testing, should use the complete test set consisting of a total of 1344 sentences, from 168 speakers.