We survey research using neural sequence-to-sequence models as computational models of morphological learning and learnability. We discuss their use in determining the predictability of inflectional exponents, in making predictions about language acquisition and in modeling language change. Finally, we make some proposals for future work in these areas. 1 introduction Theoretical morphologists have long appealed to notions of learning, or learnability, to explain language change and the varied typological patterns of the world's languages. The high-level argument is simple: all natural languages must be learned, and "unlearnable" linguistic systems cannot survive. Therefore, the learning mechanism provides constraints on what sorts of languages can exist in the world. In the realm of morphology, however, it has not proven simple to define

We examine the competition in Brazilian Portuguese 2SG direct object pronoun expression between clitic te and tonic você (e.g. Eu te vi ~ Eu vi você). We offer data from an online forced-choice survey, analyzed using mixed-effects logistic regression, to show that dialectal subject pronoun preference (tu/você) and contrast both play a significant role in conditioning this choice. Furthermore, we find that contrast, despite its traditional treatment as binary, shows gradient effects on pronoun choice- while te is the preferred DO pronoun overall, você is the variant preferred in contrastive contexts, especially in cases of double contrast.-----------------------------------------------------------------------------EVIDÊNCIAS EXPERIMENTAIS POR PREFERÊNCIAS PRONOMINAIS DE OBJETOS DIRETOS DE 2SG EM PORTUGUÊS BRASILEIROExaminamos a competição no português brasileiro entre o pronome clítico te e o tônico você para a expressão de objetos diretos de segunda pessoa singular (Eu te vi ~ Eu vi você). Apresentamos dados recolhidos de um questionário, e analizados utilizando a regressão logística de efeitos mistos, para mostrar que tanto a preferência do pronome de sujeito (você/tu) quanto o contraste têm um papel importante na escolha do pronome de objeto direto. Também, o contraste, apesar do tratamento tradicional como binário, mostra efeitos gradáveis na escolha de pronome- enquanto o te é preferido em termos globais, você é preferido em contextos contrastivos, especialmente nos casos de duplo contraste.---Original em inglês.

Purpose: Our study analyzes probabilistic constraints on subject expression previously found in adult Spanish in the speech of typically developing (TD) Spanish-speaking children and children with developmental language disorder (DLD). Previous work shows that children with DLD produce fewer overt subjects than typically developing children, and that the latter acquire constraints on subject expression as they age into adolescence. Our study complements these findings and provides further substance to the grammatical profile of children whose morphosyntactic development diverges from that of typically developing children. Method: Data are drawn from unstructured spontaneous production data from a sample of 19 monolingual Mexican, Spanish-speaking children, collected in 2006–2007. This sample includes 19 children diagnosed with DLD and 19 age-matched, typically developing children. We collected all instances of finite verbs that either did or could have occurred with a subject personal pronoun uttered by the child participants and coded them for several factors including tense–mood–aspect, switch reference, and person and number. Results: We find that children with DLD produce fewer overt subject pronouns in switch reference contexts than typically developing controls, with a significant interaction of group and switch reference. Furthermore, a discriminant function analysis shows that overt pronoun use in switch reference contexts can form part of a useful diagnostic discriminant function, with high levels of sensitivity and specificity. Conclusions: Overall, we find important differences between TD Spanish-speaking children and those diagnosed with DLD regarding rates of overt subjects and sensitivity to the probabilistic constraint of switch reference. This finding contributes to our understanding of the morphosyntactic profiles of children with DLD, as well as the utility of factors such as switch reference in the identification of language disorders.

We provide an aspectual analysis of Brazilian Portuguese predicative possessives, ter ('have') NP vs. estar com ('to be with') NP, which have been analyzed as denoting permanent versus temporary possession, respectively. Data include 20th century tokens of estar com NP (n=553) and ter NP (n=2976) from Davies' Corpus do Português. These data show that both possessive constructions can occur with the same temporal/aspectual reference and possessum, but that ter NP has a 0.55 type-token ratio while estar com NP shows significantly lower (p<0.01) productivity (0.41). An online experimental survey in which we manipulated the possessum and the duration of the possession was designed and responded to by over 200 native Brazilian participants. Results show that while both forms are possible in all contexts they are nevertheless sensitive to the duration of the possession, thus suggesting that the association with permanent versus temporary possession is pragmatic in nature. We propose that estar com NP’s possessive interval is co-extensive with the reference interval supplied by context, while ter NP’s possessive interval is a superinterval of the reference interval, like progressive and imperfective aspects, respectively (Deo 2009).