A developing child who never encounters language will not acquire it, even with all the anatomical prerequisites intact.

The anatomical evidence tells us Neanderthals could have had language.

It does not tell us whether they did.

The behavioral evidence — complex symbolic behavior of the kind that language enables — has grown substantially in the past two decades, as noted above.

Whether the accumulated evidence is sufficient to conclude that Neanderthals had language remains debated among specialists.

What the Shanidar evidence itself implies, if deliberate burial is accepted, is a level of social coordination and cultural memory that would be consistent with some form of complex communication.

Repeatedly returning to the same location to place the dead, over an extended period of time — that behavior implies a community that shared information about where the dead went and why.