SPEECH RECOGNITION 2 DAY 15 – SEPT 30, 2013 Brain & Language LING NSCI Harry Howard Tulane University

Course organization The syllabus, these slides and my recordings are available at If you want to learn more about EEG and neurolinguistics, you are welcome to participate in my lab. This is also a good way to get started on an honor's thesis. The grades are posted to Blackboard. 9/30/13Brain & Language, Harry Howard, Tulane University 2

REVIEW 9/30/13Brain & Language, Harry Howard, Tulane University 3

Review Pitch shows fundamental frequency (F 0 ) Spectrogram shows formants (F 1-3 ) Sound wave 9/30/13Brain & Language, Harry Howard, Tulane University 4

SPEECH RECOGNITION Ingram §5 9/30/13Brain & Language, Harry Howard, Tulane University 5

use Praat in class 9/30/13Brain & Language, Harry Howard, Tulane University 6

9/30/13Brain & Language, Harry Howard, Tulane University 7 Vowel articulation Tongue height: high, (mid), low put your hand under your jaw and say the vowel of: mat, met, mate, mitt, meat meat, mitt, mate, met, mat Tongue advancement: front, central, back Lip configuration: rounded, neutral, retracted

9/30/13Brain & Language, Harry Howard, Tulane University 8 Vowel description FrontCentralBack High iɪiɪ uʊuʊ (Mid) eɛeɛ ɝəɚʌɝəɚʌ oɔoɔ Low æa RetractedNeutralRounded

Sample vowel spectrograms 9/30/13Brain & Language, Harry Howard, Tulane University 9 Wide band spectrograms of the vowels of American English in a /b__d/ context. Top row, left to right: [i, ɪ, e ɪ, ɛ, æ]. Bottom row, left to right: [ ɑ, ɔ, o, ʊ, u].

Acoustic cues and distinctive features Three problems a. Input signal b. Internal representation c. Interface between (a)and (b) Lexical information retrieval but we only need the phonological form of a lexical item 9/30/13Brain & Language, Harry Howard, Tulane University 10

Why speech recognition is difficult The segmentation problem The variability problem coarticulation The speaking environment Speakers’ vocal tracts Speech rate and style Rate of information transmission 9/30/13Brain & Language, Harry Howard, Tulane University 11

Lexical retrieval Speech perception involves phonological parsing prior to lexical access It is not enough to know the lexicon beforehand. Phonetic forms and phonological representations Speech/speaker normalization Distinctive features and acoustic cues Underspecified vs. fully specified Discrete vs. continuous Hierarchical organization vs. entrainment 9/30/13Brain & Language, Harry Howard, Tulane University 12

NEXT TIME Finish Ingram §6. ☞ Go over questions at end of chapter. 9/30/13Brain & Language, Harry Howard, Tulane University 13