 To some, the sound of a baby babbling doesn't mean much, but that's not true. They're testing out vowels and consonants and trying different sounds. And by 12 months, their babbling is beginning to take on meaning, 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. Learn more at AutismSpeaks.org. Brought to you by Autism Speaks and the Ad Council.