Debates about the evolution of language are notorious for their fractious nature, and the utter lack of consensus generated; so much so, that there is a reasonably suspicion that the whole problem is empirically intractable. In this paper, I present a substantive proposal about the timing and nature of the final stage of the evolution of full human language, the transition from so-called “protolanguage” to language (though the idea rests on the idea that the initial expansion of communicative powers in our lineage was via gesture rather than voice). But though it defends a substantive proposal, the paper also (perhaps more importantly) defends and illustrates a methodological proposal too. I argue that language is a special case of a more general phenomenon — cumulative cultural evolution — and while we rarely have direct information about communication, we have more direct information about the cumulative cultural evolution of technical skill, ecological strategies and social complexity. So we can use these direct markers of information accumulation to locate, in broad terms, the period in our evolutionary history during which we became lingual.