Language as an interaction cost: An empirical study of immigrants’ literacy performances based on their origin language

1 Introduction There are currently 7.168 languages in use today, only 23 of which account for more than half of the world’s population (Eberhard, Simons and Fennig, 2023). Such a variety indicates that language is embedded in human development history and that it may have evolved concurrently with the genetic evolution of the human species. Pakendorf (2014) argues that the evolution of languages has common traits with that of genes, namely the vertical line of transmission and the retention of traces of past events. The idea is that, as for genes, language is passed down from one generation to another creating, generation by generation, a unique set of genes as well as a unique language spoken by that specific population. Moreover, genes and languages can get mixed up when parents of two different genetic and linguistic groups generate offspring. The chronological history of languages, called glottochronology, can help discover the relationship between languages and, in a broad sense, also the relationship between different human communities. Although being part of human evolution, language seems an element so familiar and present in everyday life, even in the most insignificant events and interactions that may occur, yet it is an incredibly complex notion to define. Its brief definition is that it is a system of conventional spoken, written or signed symbols, used as means of communication by members of a social group; note, here, the use of the word “conventional”, which will be later defined more in depth. Such a definition does not, however, include the incredible variety of them. Do different language systems have a common base, with slight variations among each of them, or are they each an isle with no connection to other communication systems? Chomsky’s (1957) theory of language, for example, asserts that some linguistic abilities are innate to humans, so that there may exist a universal grammar for every existing language. It is out of the scope of this work to determine how languages were born and whether they are innate to humans. However, one interesting characteristic of languages is the previously mentioned “conventionality”. A set of rules established over the course of human history, difficult to trace back, however known to every member of a group that speaks the language. We will treat language as a convention in the broader game theoretic framework of coordination games. Thus our underlying assumption about the origin of languages is that they have formed as the result of indefinitely repeated interactions (games) among players with the ultimate payoff of communicating effectively with one another. Those countless