[Language] is both a social product of the faculty of speech [that is, langage] and a collection of necessary conventions that have been adopted by a social body to permit individuals to exercise that faculty.
Language is a structure, a functioning whole in which the different parts are determined by one another.

It was found that the background linguistic system (in other words, the grammar) of each language is not merely a reproducing instrument for voicing ideas but rather is itself the shaper of ideas, the program and guide for the individual’s mental activity, for his analysis of impressions, for his synthesis of his mental stock in trade. [E]very language is a vast pattern-system, different from others, in which are culturally ordained the forms and categories by which the personality not only communicates, but analyzes nature, notices or neglects types of relationship and phenomena, channels his reasoning, and builds the house of his consciousness.

Language is the innate capacity of native speakers to understand and form grammatical sentences.
I will consider a langauge to be a set (finite or infinite) of sentences, each finite in length and constructed out of a finite set of elements.

Language as a weapon does more than establish a shared paradigm for communication. It forcefully silences or amplifies worldviews, knowledge, and dreams. In the post-colony, language is a means of suppression, an instigator of violent assimilation, and an on-going reproduction of colonial power.