Here's Science News on the topic:
"The geometry of the ear canal reveals that the hearing patterns of H. heidelbergensis overlapped with those of modern-day humans. Both modern people and the ancient hominids have especially sharp hearing in the 2 kilohertz to 4 kilohertz frequency range, where much of the sound energy of spoken language is transmitted"It's also important to note that this hearing frequency differs from that of chimpanzees, whose maximum sensitivity is range is about 4 kilohertz. This is all the more interesting because H. heidelbergensis was probably a direct ancestor of Neanderthals, not of homo sapiens.
But what this shows exactly is unclear. As Kambiz Kamrani of Anthropology.net points out:
"All this really shows is that H. heidelbergensis could hear in the frequency range as modern humans. While I think it is very possible H. heidelbergensisis communicated, this research can not indicate that they used their ‘modern ear anatomy’ for anything special."John Hawks thinks that the evidence
"seems pretty likely to indicate co-evolution of human auditory and vocal capabilities in the time before 500,000 years ago. Does that mean language? It certainly seems likely to mean some kind of vocal communication not shared with other hominoids, but that need not include every element of present-day human language."He also points out that the original research was already done in 2004 and is freely availaible for download.
Regarding theories of language evolution, I think this is fuel for the gradualist protolanguage camp (e.g. Derek Bickerton) and definitely speaks against strong versions of the gestural origins theory of language evolution.
Hat tip: Kambiz Kamrani & John Hawks