It would only be an inference, but our Neanderthal genes are a sign that Neanderthals could communicate with our more closely related ancestors. You don’t need to communicate to have sex, but the two groups of ancients probably didn’t consider each other to be totally different species. If they didn’t communicate at similar levels of understanding the interaction may not have left detectable genes today.
There is no doubt that they DID have the anatomy for spoken language. The argument that has been put forward is that they may not have been able to make all the sounds that modern human can make. But then, no modern human language uses all the sounds that modern humans can make and some, like Hawaiian, use remarkably few.
Chimps, OTOH, are extremely limited in the vocalizations they can make, and attempts to teach them spoken language have been failures even though they are able to learn quite a few hand gestures to communicate with. But the consensus these days is that their ability to use those gestures doesn’t rise to the level of “language”, mainly because they don’t seem to have a grasp of grammar. Many animals, it turns out, use vocalizations or other forms of communication to name things, although the lexicon tends to be quite small, by human standards.
That was the understanding a while ago (me, I picked it up from the Jean Auel books). As far as paleoanthropologists could tell, the hyoid bone was not positioned the same way as it is in H. sapiens, meaning that the larynx was in turn positioned in a way that did not allow for articulated speech. Later research showed that the hyoid is anchored the same way for Neanderthals as it is for us, allowing the larynx to be positioned to allow articulated speech.
Whether or not Neanderthals had vocalized speech, simple or complex, is still a matter of conjecture, with circumstantial evidence (complex tool making, art, religious ceremony) piling up on the side of complex, vocalized speech.
The new - May 17, 2014 - issue of New Scientist has an article titled How to speak Neanderthal [I linked to the full article behind the paywall - no idea if anyone else can read it; get thee to a library.].
The two-page article assumes that Neanderthals did have language and asks if any traces of it can be detected in modern languages in a way similar to Neanderthal DNA leaving some vestiges in modern human DNA.
In short, not yet. African languages - which wouldn’t have had any contact with Neanderthal language - have different rules about marking possession. But there isn’t enough yet known to tell if this is just noise from an inadequate database.
I didn’t read that article, Exapno. But I’d be very surprised if we could confidently detect any traces of Neanderthal language, even if they were still present. I am as open-minded as they come with proposals to lump language families (Nostratic, even Dene-Caucasian…hey, bring it on, as long as your “mass comparisons” of lexemes are based on real data, and not morphological or semantic fudging or special pleading), which of course implies some sort of recovery of proto-languages…but we’re talking fifteen thousand years ago at the MOST, not fifty or sixty thousand years ago.
By “African” languages, you mean just Khoi-San? Or Khoi-San and Niger-Congo? Or these plus Niger-Khordofanian? Or…? At least it sounds like the article focuses on more or less fundamental grammatical constructions (is the possessive difference a deep thing like agent-patient, which permeates the overall grammar?). But even a deep thing like this, even if it were found disproportionately in several language families on the African continent — you STILL would have a very hard time eliminating the possibility of a post-Neanderthal “sprachbund” (semantic or grammatical borrowing among genetically unrelated or distantly related languages which share a geographical area).
The article is very general and very preliminary. Here are some relevant bits.
They follow this with all sorts of caveats, so they’ve very aware that this simply might be impossible to tease out, even if it exists at all. I mentioned it mostly because they seem to have fully accepted the notion that Neanderthals had language, something that was in dispute here.
As a total sidenote, I like the fact that everybody seems to have returned to spelling it Neanderthal after a brief period in which some wanted to change the spelling to Neandertal.
But we kept the “Neandertal” pronunciation, didn’t we? (I still pronounce it as “tall”, not as “thall”.)
Dictionary.com seems to allow either pronunciation:
Thank you, Exapno, for that extract and summary. Good that they have lots of caveats.
Yeah, but they even allow nuclear to be pronounced noo-kyuh-ler. 
Isn’t -tall preferred in the relevant fields?
It’s not so much the pronunciation, it’s the spelling. Taxonomy is very conservative and the term “Neanderthal” was given before the German spelling reform changed it to Neandertal. Hence, it is H. neanderthalensis no matter which language one is writing.
The “correct” pronunciation has always been “tal”, as it is pronounced in German. I put that work in parenthesis only because “correct” is in the eye of the beholder, and the word has come into the English language pronounced as if it were an English word.
Remember when an Audi was AW-dee, but now it’s an OW-dee? And Porsche was a Porsh, not a POR-shuh? Maybe “tal” will come back in vogue as we embrace the coolness factor of our non-Sapiens ancestors. But then, I’ve always pronounced it “tal”… 
And I’ve always pronounced it “thal”. 
Pisthols at dawn.
Although the New Scientist article is paywalled, ironically, the peer reviewed article on which it appears to be based is open access.
As so often with science journalism, however, we are only getting one side (and the more “exciting” side) of the story here. Following up the clues given to me earlier in this thread by John Mace, I have found several other almost-as-recent scholarly articles defending the opposite view. Clearly the matter remains very controversial.
Incidentally, I have always pronounced it “tal” not “thal”, and so did Hotlegs.
The authors of the article are Dediu, one of the authors of that journal articles, and two of his colleagues. I can buy that the editors simplified the science and inflated its significance, but the notion that they forced the authors to assume that Neanderthals spoke a language is a step way too far.
However, it’s presented as a data point, not as an answer.
Well it is a jolly good thing that I did not say, or remotely imply, anything of the sort, then.:rolleyes:
The vast majority of linguists are going to look askance at anyone who claims to be able to trace language elements back 30,000 years. Five - Ten thousand is generally accepted as the max, with most favoring the lower number.
The antique, pre-spelling-reform way I learned to pronounce “TH” was as a voiced dental stop, somewhere between “D” and “T.” But what do I know? I still pronounce “CH” as a voiceless velar fricative (as in the classic, drawn-out ach du lieber) and tot is still todt for me (and I pronounce the “D,” sorta. German is messy like that.) My daughter laughs at my pre-WWI (my teacher was old) spelling and pronunciation, but can she decipher Fractur?
Also, remember that it’s a cognate with the English words “dale” and “dell”. And, of course, Norwegian* “dahl” as in Thor Heyerdahl. Of course, that opens the whole question of how one pronounces “Thor”… 
*and Swedish, and I presume Danish.