From birth to 3 months:
• Your baby doesn't respond or awaken to loud, sudden noises.
• Your baby isn't soothed by your voice.
From 3 to 6 months:
• Your baby doesn't look at you or react when you talk, sing, or make funny noises.
• Your baby doesn't turn her head to see where a sound has come from.
From 6 to 10 months:
• Your baby isn't babbling or attempting to imitate and match sounds like "ga" and "da."
• Your baby doesn't respond to her name.
From 10 to 15 months:
• Your baby can't locate or point to familiar objects when asked.
• Your baby doesn't understand simple sentences like "Where's the kitty?"
From 15 to 18 months:
• Your baby doesn't recognize words for common things, like parts of the body, in response to questions.
• Your baby doesn't say a few simple words.
• Your baby can't follow simple spoken directions.
If your notice any of these issues, give your pediatrician a call, since the earlier hearing loss is diagnosed, the more likely treatments like hearing aids, speech therapy, and cochlear implants (surgically implanted devices that provide a sense of sound) will help prevent speech and language delays. In fact, one study found that children whose hearing loss was detected by 6 months had normal language skills by age 3, while children who were diagnosed later were more likely to be behind. --Julie Evans
Originally published in American Baby magazine, November 2004. Updated 2009.