By 9 months: Little or no back-and-forth sharing of sounds, smiles or other facial expressions
By 12 months: Little or no babbling, Little or no back-and-forth gestures such as pointing, showing, reaching or waving, Little or no response to name
By 16 months: Very few or no words
By 24 months: Very few or no meaningful, two-word phrases (not including imitating or repeating)
At any age: Loss of previously acquired speech, babbling or social skills, Avoidance of eye contact, Persistent preference for solitude, Difficulty understanding other people’s feelings, Delayed language development, Persistent repetition of words or phrases (echolalia), Resistance to minor changes in routine or surroundings, Repetitive behaviors (flapping, rocking, spinning, etc.), Unusual and intense reactions to sounds, smells, tastes, textures, lights and/or colors
Do you suspect that your feelings and behaviors involve autism? Many children who have milder forms of autism go undiagnosed until adulthood.