In this article, we argue that our distinctive ability for cross-modal categorization evolved from amodal categorization, an ability shared with non-human animals, under the gradual influence of human self-domestication (HSD). In turn, this improved ability fostered both lexicalization and syntactic combinatorics (Merge) abilities and paved the way towards the emergence of our distinctive faculty of language and, ultimately, of modern languages.
Benítez‐Burraco et al. (Mon,) studied this question.