The centrality of speech for human thought
Speech is not language. But without speech/sign there would be neither language nor mostly human thought. A divide between an internal wordless system and an external instrumental one for speech/sign is conceptually and empirically problematic; and evolutionarily costly. Such a divide is however assumed by otherwise opposite trends (represented, say, by Tomasello and Chomsky). An alternative view where speech and rational thought are linguistic seems better supported by facts on words, modalities (spoken and signed) and brain correlates. Evolutionarily, this view leads to place a vocal learning capacity, which is exceptional among primates, as central in language evolution. Such a capacity, run by a powerful computational system, provided Sapiens with a platform for the invention of words.