But how did protolanguage actually start?

In dealing with the nature of protolanguage, an important formative factor in its development, and one that would surely have influenced that nature, has too often been neglected: the precise circumstances under which protolanguage arose. Three factors are involved in this neglect: a failure to appreciate radical differences between the functions of language and animal communication, a failure to relate developments to the overall course of human evolution, and the supposition that protolanguage represents a package, rather than a series of separate developments that sequentially impacted the communication of pre-humans. An approach that takes these factors into account is very briefly suggested.