Carnap : a language, as e.g. English, is a system of activities or, rather, of habits, i.e., dispositions to certain activities, serving mainly for the purposes of communication and of co-ordination of activities among the members of a group.

Morris : A language in the full semiotical sense of the term is any intersubjective set of sign vehicles whose usage is determined by syntactical, semantical, and pragmatical rules. | Szober : We shall call phonic language the set of sounds used for the purpose of establishing communication with one's milieu or reproduced in one's mind for thhttps://en.wikiquote.org/wiki/Special:RecentChangese purpose of clearly realizing one's own thought. | p. 314 footnote