Shortlyafterbirth, synapsesformat a ratethat's fasterthananyothertimeperiodinourlives--it's knownastheexuberantperiodwhere a youngbraincancreateuptotwomillionsynapseseverysecond.
Thenumberofsynapsesyouhavepeaksbetweentheagesof 4 to 8, butyourbrainstillhas a lotofplasticityuntilpuberty.
Thatiswhyexposuretolanguageatanearlyagemakessuch a bigdifference.
Now, althoughLenneberg's CriticalPeriodhypothesisstatesthatthattheidealwindowtoacquirelanguageisage 2 to 13, synapsesinthebrain's cortexactuallystartformingmuchearlierthanthat, duringthesecondtrimesterofpregnancy.
Andthere's prettyconvincingresearchthatshowslanguagedevelopmentstartsbefore a baby's evenborn, soit's probablynevertoosoonfor a pregnantmothertospeaktoherbaby.