Word hypothesis from undifferentiated, errorful phonetic strings

This thesis investigates a dynamic programming approach to word hypothesis in the context of a speaker independent, large vocabulary, continuous speech recognition system. Using a method known as Dynamic Time Warping, an undifferentiated phonetic string (one without word boundaries) is parsed to produce all possible words contained in a domain specific lexicon. Dynamic Time Warping is a common method of sequence comparison used in matching the acoustic feature vectors representing an unknown input utterance and some reference utterance. The cumulative least cost path, when compared with some threshold can be used as a decision criterion for recognition. This thesis attempts to extend the DTW technique using strings of phonetic symbols, instead. Three variables that were found to affect the parsing process include: (1) minimum distance threshold, (2) the number of word candidates accepted at any given phonetic index, and (3) the lexical search space used for reference pattern comparisons. The performance of this parser as a function of these variables is discussed. Also discussed is the performance of the parser at a variety of input error conditions

Loanword adaptation as first-language phonological perception

We show that loanword adaptation can be understood entirely in terms of phonological and phonetic comprehension and production mechanisms in the first language. We provide explicit accounts of several loanword adaptation phenomena (in Korean) in terms of an Optimality-Theoretic grammar model with the same three levels of representation that are needed to describe L1 phonology: the underlying form, the phonological surface form, and the auditory-phonetic form. The model is bidirectional, i.e., the same constraints and rankings are used by the listener and by the speaker. These constraints and rankings are the same for L1 processing and loanword adaptation

Acoustic-phonetic constraints in continuous speech recognition: a case study using the digit vocabulary.

Thesis (Ph.D.)—Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1985.Includes bibliographical references (leaves 155-159).This electronic version was scanned from a copy of the thesis on file at the Speech Communication Group. The certified thesis is available in the Institute Archives and Special Collections.Vinton-Hayes Fellowship. DARPA, monitored through the Office of Naval Research. System Development Foundation.Ph.D

Tone classification of syllable -segmented Thai speech based on multilayer perceptron

Thai is a monosyllabic and tonal language. Thai makes use of tone to convey lexical information about the meaning of a syllable. Thai has five distinctive tones and each tone is well represented by a single F0 contour pattern. In general, a Thai syllable with a different tone has a different lexical meaning. Thus, to completely recognize a spoken Thai syllable, a speech recognition system has not only to recognize a base syllable but also to correctly identify a tone. Hence, tone classification of Thai speech is an essential part of a Thai speech recognition system.;In this study, a tone classification of syllable-segmented Thai speech which incorporates the effects of tonal coarticulation, stress and intonation was developed. Automatic syllable segmentation, which performs the segmentation on the training and test utterances into syllable units, was also developed. The acoustical features including fundamental frequency (F0), duration, and energy extracted from the processing syllable and neighboring syllables were used as the main discriminating features. A multilayer perceptron (MLP) trained by backpropagation method was employed to classify these features. The proposed system was evaluated on 920 test utterances spoken by five male and three female Thai speakers who also uttered the training speech. The proposed system achieved an average accuracy rate of 91.36%

Syllable-based constraints on properties of English sounds

Also issued as Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1989.Includes bibliographical references (p. 169-174).Work sponsored in part by the Office of Naval Research. N00014-82-K-0727Mark A. Randolph

Loan Phonology

For many different reasons, speakers borrow words from other languages to fill gaps in their own lexical inventory. The past ten years have been characterized by a great interest among phonologists in the issue of how the nativization of loanwords occurs. The general feeling is that loanword nativization provides a direct window for observing how acoustic cues are categorized in terms of the distinctive features relevant to the L1 phonological system as well as for studying L1 phonological processes in action and thus to the true synchronic phonology of L1. The collection of essays presented in this volume provides an overview of the complex issues phonologists face when investigating this phenomenon and, more generally, the ways in which unfamiliar sounds and sound sequences are adapted to converge with the native language’s sound pattern. This book is of interest to theoretical phonologists as well as to linguists interested in language contact phenomena

Automatic syllable detection for vowel landmarks

Supervised by Kenneth N. Stevens.Also issued as Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 192-200).by Andrew Wilson Howitt

Subword lexical modelling for speech recognition

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 155-160).by Raymond Lau.Ph.D