Human language has syntax, a set of rules for connecting words together to make statements and question. Language can also be changed, by adding new words, for example, to describe new things. Other animals may inherit a set of calls which have pre-set functions.
Language may be done by speech or by writing or by moving the hands to make signs. It follows that language is not just any way of communicating. Even some human communication is not language: see non-verbal communication. Humans also use language for thinking.
Language is a word that may be used by extension:
The language of a community or country.
The faculty of speech.
Formal language in mathematics, logic and computing.
Sign language for people who cannot hear.
A type of school subject.
UNESCO says that 2,500 languages are at risk of becoming extinct.