Summarize the following:
By 7 months old, typical babies express happiness and smile. A baby's first smile often occurs even before 3 months. If a baby doesn't follow objects with its eyes by 3 months, this could be a very early indicator of autism. Observe their other facial expressions. By 9 months old, babies communicate with others by displaying certain expressions like grimacing, pouting and grinning to fit their mood. Babies that develop typically will babble by the time they are 7 months old. The noise might not make any sense. It is common for babies to make repetitive sounds, but autistic babies will make different sounds and rhythms. By seven months, non-autistic children are able to laugh and make squealing sounds. Some autistic children experience a delay in speaking, or never learn to speak at all. Around 15-20% of autistic people never speak, although this does not mean they do not communicate. By one year, non-autistic children are able to say single words such as "Mama" and "Dada". By age 2, most children are able to string words together. A typical 2-year-old should have a vocabulary of more than 15 words. An autistic child might not respond to their own name or avoid play with others. By 7 months, a typical child responds to simple games like peekaboo. A non-autistic child responds to its own name at about one year old. By 18 months, a typical child will start to play "pretend" games, such as pretend feeding a baby doll. Autistic children tend not to play pretend, and may appear unimaginative to onlookers. By age two, non-autistic children will imitate your words and actions. Pay attention to speech regression. Some infants meet their milestones and then lose skills at an older age. Babies will reach for objects typically by 7 months of age. Place a toy out of your child's reach to see if he will reach for it. Babies as young as 7 months old will try to attract your attention with movements. Autistic children may be less active. By 6 months old, children should turn their head towards sounds they hear. If your child does not do this they may have a hearing problem, or early symptoms of autism. Many babies start waving bye-bye and pointing to objects they want by the time they are 12 months old. If your child has not started to walk or crawl by 12 months, this is a very serious developmental disability. By age 1, most babies will start to use gestures such as shaking their head to say "no". If your child cannot walk by age 2, you should definitely have them evaluated by a doctor for autism and other disabilities. Stimming serves a variety of purposes: from self-calming to expressing emotions. If your young child waves their hands, rocks their body, or spins in circles constantly, this is a likely sign of autism.
Note your baby's facial expression. Notice when babbling begins. Consider when your child begins speaking. Check your child's response to language and play. Examine your child's movements. Look for stimming.