> Individuals with HAQERs that conferred greater language skills were also more likely to have larger heads, but in order to walk upright, humans need narrower pelvises. The evolutionary conflict between the two traits is why HAQER variants associated with stronger language skills seem to have stalled out, researchers say. This obstetric dilemma could also explain why Neanderthals seem to have HAQER variants more strongly associated with language skills than humans, but the team says further research is needed to say for sure.

I read somewhere that since the advent of the safe caesarean section, pelvises have started to average slightly narrower, since a narrow pelvis is no longer a death sentence for a woman and her potential offspring. So presumably that might relieve the evolutionary pressure on head size as well, allowing further evolution in language abilities.

Looks like they could if they were willing to lower their sophistication a bit, and maybe also use more slang and jargon.

Plus not be such sticklers when it comes to grammar ;)