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The languages of Mesolithic western Europe were completely replaced by the languages brought by subsequent immigrant populations.

The Neolithic farmers who replaced the WHG across Europe brought their languages with them.

The Bronze Age steppe pastoralists brought Proto-Indo-European, which is the ancestor of virtually all the languages of modern Europe including English.

Whatever language Cheddar Man spoke — whatever words his community used for the hills they hunted, the animals they pursued, the ceremonies they practiced, the stories they told — is entirely gone.

Not a word survives.