Ask yourself how different is an enculturated ape's use of human language from that of an exceptional dog like Fellow or parrot like Alex?
(And speaking of exceptional, what is the variability in apes performance? One of the remarkable facts of human language acquisition, is that it is very uniform across a wide range of children and experiences. This may reflect the much less genetic variability of humans in contrast to other large primates.)
Finally what we can begin to speculate on what kind of genetic changes might have occurred to evolve language in concert with evolving culture. (See recent reports in News and the old Limber, 1982 ).
Here are some additional comments and resources.
Limber, J. (1973). The genesis of complex sentences. In T. Moore (Ed.), Cognitive Development and the Acquisition of Language (pp. 169-186). New York: Academic Press.
Limber, J. (1977). Language in child and chimp? American Psychologist, 32, 280-295 (Reprinted in Sebeok, T. & Sebeok, J. (Eds.) (1980). Speaking of Apes (pp.1197-1218). New York: Plenum Press.)
Limber, J. (1982). What can chimps tell us about the origins of language. In S. Kuczaj (Ed.), Language Development: Volume 2 (pp. 429-446). Hillsdale, NJ: L. E. Erlbaum.