Parents provide their children with genes as well as an environment, so the fact that talkative parents have kids with good language skills could simply mean that and that the same genes that make parents talkative make children articulate.

1126/science. ; Pinker S. Criticism
The Language Instinct has been criticized by Geoffrey Sampson in his book The 'Language Instinct' Debate.

Steven Arthur Pinker (born September 18 1954) is a Canadian-born experimental psychologist cognitive scientist linguist and popular science author. In his popular books he has argued that language is an "instinct" or biological adaptation shaped by natural selection.