summaries and reviews

Speech recognition: Recognizing the familiar, generalizing to the similar, and adapting to the novel

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At long last, we have finished a substantial revision of Dave Kleinschmidt‘s opus “Robust speech perception: Recognize the familiar, generalize to the similar, and adapt to the novel“. It’s still under review, but we’re excited about it and wanted to share what we have right now.

Phonetic recalibration via belief updating
Figure 1: Modeling changes in phonetic classification as belief updating. After repeatedly hearing a VOT that is ambiguous between /b/ and /p/ but occurs in a word where it can only be a /b/, listeners change their classification of that sound, calling it a /b/ much more often. We model this as a belief updating process, where listeners track the underlying distribution of cues associated with the /b/ and /p/ categories (or the generative model), and then use their beliefs about those distributions to guide classification behavior later on.

The paper builds on a large body of research in speech perception and adaptation, as well as distributional learning in other domains to develop a normative framework of how we manage to understand each other despite the infamous lack of invariance. At the core of the proposal stands the (old, but often under-appreciated) idea that variability in the speech signal is often structured (i.e., conditioned on other variables in the world) and that an ideal observer should take advantage of that structure. This makes speech perception a problem of inference under uncertainty at multiple different levels Read the rest of this entry »


“Gradience in Grammar” workshop at CSLI, Stanford (#gradience2014)

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A few days ago, I presented at the Gradience in Grammar workshop organized by Joan Bresnan, Dan Lassiter , and Annie Zaenen at Stanford’s CSLI (1/17-18). The discussion and audience reactions (incl. lack of reaction in some parts of the audience) prompted a few thoughts/questions about Gradience, Grammar, and to what extent the meaning of generative has survived in the modern day generative grammar. I decided to break this up into two posts. This summarizes the workshop – thanks to Annie, Dan, and Joan for putting this together!

The stated goal of the workshop was (quoting from the website):

For most linguists it is now clear that most, if not all, grammaticality judgments are graded. This insight is leading to a renewed interest in implicit knowledge of “soft” grammatical constraints and generalizations from statistical learning and in probabilistic or variable models of grammar, such as probabilistic or exemplar-based grammars. This workshop aims to stimulate discussion of the empirical techniques and linguistic models that gradience in grammar calls for, by bringing internationally known speakers representing various perspectives on the cognitive science of grammar from linguistics, psychology, and computation. 

Apologies in advance for butchering the presenters’ points with my highly subjective summary; feel free to comment. Two of the talks demonstrated

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more from LSA 2009

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Hal Tily gave an interesting talk about how processing factors influencing synchronic word order variation ultimately lead to diachronic word order change, focusing on the SOV-SVO variation in Old English. Locality-based processing constraints lead speakers to prefer orders which minimize the distance between syntactically dependent elements (Hawkins 2004, Gibson 2000). All things being equal, then, SVO structures will be preferable to SOV structures, and this preference will be more pronounced as the weight of the object increases. With no additional pressure making SOV structures preferable in circumstances where weight does not play much of a role, SVO structures will become more frequent (and in fact they do). The next question is how does the synchronic production preference eventually lead to diachronic change. Hal suggests that language learners are inducing structure based on their input and do not correct for processing factors such as weight. A simulation shows that VO order will become dominant (and effectively grammaticalized) in a situation where language users select utterances in a way that is sensitive to weight, but where language learners essentially estimate a regression without a term for weight. Of course questions remain: why was there SOV in Old English to begin with, if there is an over-arching preference for SVO? Why aren’t all languages SVO? Maybe SOV structures had the same sorts of processing advantages (anti-locality effects) that modern verb-final languages seem to have, and these gradually dried up as the English case system disappeared….In any case, I thought this study nicely illustrated a way of linking processing phenomena and language change, and it raises some interesting questions.

Article Summary: Yamashita and Chang (2001)

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Here’s a quick summary of an article about phrasal ordering preferences by H. Yamashita and F. Chang, published 2001 in Cognition. The title of the paper is “Long before short” preference in the production of a head-final language. Enjoy.

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