Even before the theory of evolution made discussion of more animal-like human ancestors common place, philosophical and scientific speculation concerning the origins of language, implying that human ancestors once had no language, have been frequent throughout history. In modern Western Philosophy, speculation by authors such as Thomas Hobbes, and later Jean-Jacques Rousseau lead to the Académie française even declaring the subject off bounds.
The subject is of such interest to philosophy because language is such an essential characteristic of human life. In classical Greek philosophy such questions were connected to the subject of the natures of things, in this case human nature. Therefore already in Aristotle language is mentioned in discussions of the natural propensities of humans to be political and to dwell in city-state types of communities, to engage in pair-bonding, and so on.
Hobbes followed by John Locke and others claimed that language is an extension of the "speech" which humans have with themselves, which in a sense takes the classical view that reason is one of the most primary characteristics of human nature. Others have argued the opposite - that reason developed out of the need for more complex communication. Rousseau, despite writing before the publication of Darwin's theory of evolution, claimed that there had once been humans who had no language or reason and who developed language first, rather than reason - the development of which things he explicitly described as a mixed blessing, with many negative characteristics.