Full Idea
Language is as old as consciousness, language is practical consciousness that exists also for other men.
Gist of Idea
Language co-exists with consciousness, and makes it social
Source
K Marx / F Engels (The German Ideology [1846], §1.A)
Book Reference
Marx,K./Engels,F.: 'The German Ideology', ed/tr. Arthur,C.J. [Lawrence and Wishart 1985], p.51
A Reaction
Dennett takes a similar view - that consciousness is more-or-less a consequence of the development of consciousness. This is understandable if you make intentional rather than phenomenal consciousness central. Otherwise ants may well have it.