Ryan Cotterell

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String similarity is most often measured by weighted or unweighted edit distance d(x, y). Ristad and Yianilos (1998) defined stochastic edit distance—a probability distribution p(y | x) whose parameters can be trained from data. We generalize this so that the probability of choosing each edit operation can depend on contex-tual features. We show how to(More)
We present LEMMING, a modular log-linear model that jointly models lemmati-zation and tagging and supports the integration of arbitrary global features. It is trainable on corpora annotated with gold standard tags and lemmata and does not rely on morphological dictionaries or an-alyzers. LEMMING sets the new state of the art in token-based statistical(More)
We present labeled morphological segmentation—an alternative view of morphological processing that unifies several tasks. We introduce a new hierarchy of morphotactic tagsets and CHIPMUNK, a discriminative morphological segmen-tation system that, contrary to previous work, explicitly models morphotactics. We show improved performance on three tasks for all(More)
This paper presents a multi-dialect, multi-genre, human annotated corpus of dialectal Arabic with data obtained from both online newspaper commentary and Twitter. Most Arabic corpora are small and focus on Modern Standard Arabic (MSA). There has been recent interest, however, in the construction of dialectal Arabic corpora (Zaidan and Callison-Burch, 2011a;(More)
The 2016 SIGMORPHON Shared Task was devoted to the problem of morphological reinflection. It introduced morphological datasets for 10 languages with diverse ty-pological characteristics. The shared task drew submissions from 9 teams representing 11 institutions reflecting a variety of approaches to addressing supervised learning of reinflection. For the(More)
The observed pronunciations or spellings of words are often explained as arising from the " underlying forms " of their morphemes. These forms are latent strings that linguists try to reconstruct by hand. We propose to reconstruct them automatically at scale, enabling generalization to new words. Given some surface word types of a concatenative language(More)
Arabic is not just one language, but rather a collection of dialects in addition to Modern Standard Arabic (MSA). While MSA is used in formal situations, dialects are the language of every day life. Until recently, there was very little dialectal Arabic in written form. With the advent of social-media, however, the landscape has changed. We provide the(More)
Technology Center of Excellence. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsor. Abstract We describe a multilingual named entity recognition system using language independent feature templates, designed for processing short, informal(More)
We present penalized expectation propagation (PEP), a novel algorithm for approximate inference in graphical models. Expectation propagation is a variant of loopy belief propagation that keeps messages tractable by projecting them back into a given family of functions. Our extension, PEP, uses a structured-sparsity penalty to encourage simple messages ,(More)