While crows have "crafty" intelligence, neanderthals would be more apt at this.
But really, the logical first language would be gesture, an extension of already existing body language. And such language is employed by humans when hunting, at war, whenever quiet is preferred.
Even a gesture language of a few dozen concepts is almost automatic, pointing, waving, directional motions, hushing motions, pointing at your head, clapping, etc.
This being extended as full language in beings incapable of complex sound, seems viable.