This article about the link between gestures and future vocabulary is interesting, but fatally flawed.
Vocabulary size tallies strongly with a child's academic success, so it's striking that the lexical gap between rich and poor appears when children are still toddlers and can continue throughout their school life. What is it about a family's socioeconomic status that so strongly affects their child's linguistic fate at such an early age?
That's not striking to me. It seems very likely that socioeconomic status and "linguistic fate" are both effects of the same underlying cause-that-shall-not-be-named: smarter genes.