Not only are languages phonetic in character; they are also 'phonemic'. Between the articulation of the voice into the phonetic sequence [...], and the complicated patterning of phonetic sequences into [...] words, phrases, and sentences there is a very interesting process of phonetic selection and generalization which is easily overlooked but which is crucial for the development of the specifically symbolic aspect of language. Language is not merely articulated sound; its significant structure is dependent upon the unconscious selection of a fixed number of [...] 'sound units'.
- Sapir (1933a), a pag.8