 By six months, they're combining vowels and consonants. By nine months, they're trying out different kinds of sounds. And by 12 months, their babbling is beginning to take on some meaning. ABC News, I'm Sheri Preston. Hurricane Beryl plowing through the southeast Caribbean... Especially if there's no babbling at all. Little to no babbling by 12 months or later is just one of the possible signs of autism in children.