A report I found today in Science News suggests that early hominids had hearing capabilities similar to modern humans, and paleoanthropologists at the American Natural History Museum in New York believe that this could indicate that they had some form of language.
Analysis and reconstruction of the auditory bones in skills of Homo heidelbergensis dating from 530,000 years ago have demonstrated that their hearing was probably similar to that of modern humans. They could hear best between 2 khz and 4 khz, the frequency range within which much of the sound of speech is transmitted, and researchers believe that such an ability must have been used, as maintaining such sensory systems is neurologically very expensive and they are unlikely to evolve and not be used. Whether they were connected with speech or something else is not known.
I think it is hard to tell everything (even the range of frequencies) just by analyzing the bones. There is the matter of soft tissues which control most of things in the body more than bones do. Yet, I think it is normal to have a form of a language for such species. Animals do have communication systems, so why not hominids.