In Bill Bryson's book, The Mother Tongue, he says it is likely that Homo Sapiens had a pretty sophisticated language capability (p. 23), but that the Neanderthals may have been more confined to things like, "I'm hungry. Let's hunt." He goes on:
It may be no more than intriguing coincidence, but the area of Cro-Magnon's cave paintings is also the area containing Europe's oldest and most mysterious ethnic group, the Basques. Their language, called Euskara by its speakers, may be the last surviving remnant of the Neolithic languages spoken in Stone Age Europe and later displaced by Indo-European tongues."