Language convergence is a type of linguistic change in which languages come to resemble one another structurally as a result of prolonged language contact and mutual interference, regardless of whether those languages belong to the same language family, i.e. stem from a common genealogical proto-language. In contrast to other contact-induced language changes like creolization or the formation of mixed languages, convergence refers to a mutual process that results in changes in all the languages involved. The term refers to changes in systematic linguistic patterns of the languages in contact (phonology, prosody, syntax, morphology) rather than alterations of individual lexical items. Contexts Language convergence occurs in geographic areas with two or more languages in contact, resulting in groups of languages with similar linguistic features that were not inherited from each language's proto-language. These geographic and linguistic groups are called linguistic areas, or Sprachbund areas. Linguistic features shared by the languages in a language area as a result of language convergence are called areal features. In situations with many languages in contact and a variety of areal features, linguists may use the term language convergence to indicate the impossibility of locating a singular source for each areal feature. However, as the classification of linguistic areas and language convergence depends on shared areal features, linguists must distinguish between areal features resulting from convergence and internally motivated changes resulting in chance similarities between languages. Language convergence can also occur for a particular person's grammar. It sometimes occurs in children who are acquiring a second language. Because the grammar of the child's native language is still developing the grammar patterns of the first and second language can influence each other. Singaporean students learning both English and Mandarin showed use of common Mandarin grammatical structures when speaking English. Mechanisms Language convergence occurs primarily through diffusion, the spread of a feature from one language to another. The causes of language convergence are highly dependent on the specifics of the contact between the languages involved. Often, convergence is motivated by bilingual code-switching or code-alternation. Seeking full expressive capacity in both languages, bilingual speakers identify preexisting parallels between languages and use these structures to express similar meanings, eventually leading to convergence or increasing the frequency of the similar patterns. Sociolinguistic factors may also influence the effects of language convergence, as ethnic boundaries can function as barriers to language convergence. Ethnic boundaries may help to explain areas in which linguists’