Language Evolution and Computation Bibliography

Creole is a new born language emerging in most cases where language contact takes place. Simulating behaviors that creole communities are formed in some environments, we could contribute to actual proof of some linguistic theories concerning language acquisition. Thus far, a simulation study of the emergence of creoles has been reported in the mathematical framework. In this paper we introduce a spatial structure to the framework. We show that local creole communities are organized, and creolization may occur when language learners learn of ten from non-parental language speakers, in contrast to the non-spatial model. The quantitative analysis of the result tells us that emergence of local colonies at the early stage tends to induce the full creolization.

The inflection of words based on agreement, such as number, gender and case, is considered to contribute to clarify the dependency between words in a sentence. Our purpose in this study is to investigate the efficiency of word inflections with HPSG (Head-driven Phrase Structure Grammar), which is able to deal with these features directly. Using a notion of utility, we measure the efficiency of a grammar in terms of the balance between the number of semantic structures of a sentence, and the cost of agreement according to the number of unification processes. In our experiments, we showed how these were balanced in two different corpora. One, WSJ (Wall Street Journal), includes long and complicated sentences, while the other corpus, ATIS (Air Travel Information System) does shorter colloquial sentences. In the both corpora, agreement is surely important to reduce ambiguity. However, the importance of agreement in the ATIS corpus became salient as personal pronouns were so often employed in it, compared with the WSJ corpus.

Language change is considered as a transition of population among languages. The language dynamics equation represents such a transition of population. Our purpose in this paper is to develop a new formalism of language dynamics for a real situation of language contact. We assume a situation that memoryless learners are exposed to a number of languages. We show experimental results, in which contact with other language speakers during acquisition period deteriorates the learning accuracy and prevents the emergence of a dominant language. If we suppose a communicative language, when learners are frequently exposed to a variety of languages, the language earns relatively higher rate of population. We discuss the communicative language from the viewpoint of the language bioprogram hypothesis.

Creole is one of the main topics in various fields concerning the language origin and the language change, such as sociolinguistics, the developmental psychology of language, paleoanthropology and so on. Our purpose in this paper is to develop an evolutionary theory of language to study the emergence of creole. We discuss how the emergence of creole is dealt with in the perspective of population dynamics. The proposal of evolutionary equations is a modification of the language dynamics equations by Komarova et al. We show experimental results, in which we could observe the emergence of creole. Furthermore, we analyze the condition of creolization in terms of similarity among languages. We conclude that a creole becomes dominant when pre-existing languages are not similar to each other and rather similar to the newly appeared language (would-be-creole); however the new language must not be too similar, in which case pre-existing languages remain and coexist.

Children will develop their parental languages correctly, since language learners come to obtain the one which they contact most in the community. At the same time, children would be affected by other languages, the influence of which is proportional to the population of those languages. In this paper, we revise the foregoing evolutionary theory of language, that is differential equations of the population dynamics. We propose that the transition rate in languages is sensitive to the distribution of population of each generation. In addition, we introduce the exposure probability that is the measure of influence from other languages. We show experimental results, in which we could observe the emergence of creole. Furthermore, we analysed which language would be dominant, dependent on the initial distribution of population, together with the exposure probability.