~ ROA Version, 8/2002. Essentially identical to the Tech Report, with new pagination (but the same footnote and example numbering); correction of typos, oversights & outright errors; improved typography; and occasional small-scale clarificatory rewordings. Citation should include reference to this version.

T he distinction between marked and unmarked structures has played a role throughout this century in the development of phonology and of linguistics generally. Optimality Theory (Prince and Smolensky 1993) offers an approach to linguistic theory that aims to combine an empirically adequate theory of

Prosodic phrase structure

The study of phonotactics (e.g., the ability of English speakers to distinguish possible words like blick from impossible words like *bnick) is a central topic in phonology. We propose a theory of phonotactic grammars and a learning algorithm that constructs such grammars from positive evidence. Our grammars consist of constraints that are assigned numerical weights according to the principle of maximum entropy. Possible words are assessed by these grammars based on the weighted sum of their constraint violations. The learning algorithm yields grammars that can capture both categorical and gradient phonotactic patterns. The algorithm is not provided with any constraints in advance, but uses its own resources to form constraints and weight them. A baseline model, in which Universal Grammar is reduced to a feature set and an SPE-style constraint format, suffices to learn many phonotactic phenomena. In order to learn nonlocal phenomena such as stress and vowel harmony, it is necessary to augment the model with autosegmental tiers and metrical grids. Our results thus offer novel, learning-theoretic support for such representations. We apply the model to English syllable onsets, Shona vowel harmony, quantity-insensitive stress typology, and the full phonotactics of Wargamay, showing that the learned grammars capture the distributional generalizations of these languages and accurately predict the findings of a phonotactic experiment.

Abstract not found

This paper discusses a perceptron model of the learning and assignment of linguistic stress, using data from nineteen human languages. First, we point out some interesting parallels between aspects of the model and the constructs and predictions of metrical phonology, the linguistic theory of stress. Second, we develop a novel analysis of linguistic stress in terms of ease of perceptron-learnability. These two sets of results suggest that simple statistical learning techniques have the potential to complement, and provide computational validation for, abstract theoretical investigations of language. We then examine why such methodologies should be of interest for linguistic theorizing. Our analysis began at a high level by observing inherent characteristics of various stress systems, much as theoretical linguistics does. However, our explanations changed substantially whenwe included a detailed account of the model's processing mechanisms. Our higher-level, theoretical accou...

We describe the modification of a grammar to take ad-vantage of prosodic information automatically extracted from speech. The work includes (1) the development of an integer "break index " representation of prosodic phrase boundary information, (2) the automatic detec-tion of prosodic phrase breaks using a hidden Markov model on relative duration of phonetic segments, and (3) the integration of the prosodic phrase break informa-tion in SRI's Spoken Language System to rule out alter-native parses in otherwise syntactically ambiguous sen-tences. Initial experiments using ambiguous sentences read by radio announcers achieved good results in both detection and parsing. Automatically detected phrase break indices had a correlation greater than 0.86 with hand-labeled data for speaker-dependent models; and, in a subset of sentences with preposition ambiguities, the number of parses was reduced by 25 % with a simple grammar modification.

Abstract not found

In recent years, we have seen a real deepening of our understanding of the nature of poetic meter and the English metrical system. In part, this has resulted from the application ofthe formal methods oflinguistics to metrical study-the willingness to formulate metrical rules explicitly and to check out their consequences has naturally led to progress. However, the new results also depend on recent advances in notions of prosodic phonological structure, as an account of a metrical system can only be as adequate as the theory of prosodic structure on which it is based. In particular, the work of Kiparsky (1977) has shown that the metrical theory of stress, as developed in Liberman and Prince (1977) and other works, provides the basis for a more adequate and explanatory theory of English meter than the numerological stress representation of The Sound Pattern of English. Kiparsky's work has in turn repaid its debt to metrical stress theory-it is surely an argument in favor of Liberman and Prince's system that it can illuminate the facts ofEnglish meter so welL At the level ofdescriptive adequacy that has now been reached, it is fair to say that the study of meter can serve as a window into phonological structure. With this purpose in mind, I offer here what I believe to be an improvement on Kiparsky's analysis; one that simplifies the rules, accounts for the data more accurately.., and links up the English system with what is known about metrical systems in generaL These improvements are the result of basing the rules on a different representation of English stress, drawn again from the work of Liberman and Prince (1977). I argue that the aspects of stress that are relevant to meter are embodied not in metrical trees, as Kiparsky assumes, but rather in metrical grids, which Liberman and Prince develop at the end of their paper in a treatment of rhythmic stress clashes. My goals are to clarify the metrical system of English and to shed light on a current controversy concerning the proper representation of stress. 1. Kiparsky's System and Its Drawbacks I will begin with a brief summary of the proposals of Kiparsky (1977) (hereafter K). Like most metricists, Kiparsky views a metrical system as a set of rules determining when

Languages are felt to be spoken with different kinds of rhythm. Traditional accounts have proposed that some languages are "stress-timed", while others are "syllable-timed". Despite the intuitive appeal of this typology, however, there is little phonetic evidence for the distinction. Meanwhile, generative phonology fails to provide clear explications on how formal representations of linguistic rhythm are to be phonetically interpreted. This thesis compared the rhythmic organization of English and Japanese using a novel experimental method, called "speech cycling", in which subjects produce a given phrase repeatedly in time with a controlled metronome. The task induces overtly rhythmic forms of speaking, and overcomes difficulties encountered by earlier studies in finding reliable physical correlates of speech rhythm and its variation across languages. In Experiment 1, subjects were asked to repeat phrases at a continuum of speaking rates, in order to examine whether they would fall in ...