My completely non-scientific hypothesis is that sign languages were the first languages. I base this on the idea that hominids have been constructing tools with

My completely non-scientific hypothesis is that sign languages were the first languages. I base this on the idea that hominids have been constructing tools with their hands for millions of years, but, as far as we know, modern human vocal chords have only existed for hundreds of thousands of years. It seems more likely to me that they would have created a language with their hands first, and then adapted that technogy to speech once sufficiently complex voice boxes came into play.