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.
(HT: NW.)
Genes are a relevant factor, but I would expect more influence from the quality of parental involvement. The key sentence from that article:
"When Rowe and Goldin-Meadow adjusted for parental gesturing, the link between wealth and a child's use of gestures was severely weakened."
You two are finding out first hand how difficult it is to raise an infant, and how many opportunities there are to give it more or less attention. A baby is born with about half of its adult brain weight, and by one year has about 90%. So when you interact with your infant, its brain is wiring itself according to what you're teaching. There's a great book on this titled Why Love Matters, by Sue Gerhardt. Some of the biochemistry gets pretty detailed, but it will leave you with no doubt that the quality of the infant's early emotional experiences has far-reaching effects on how the brain itself forms and functions.
Well that's just scary, thanks! :)