3-6 months: This is an aggressive time to start signing so don’t expect to see baby sign back just yet. While babies are too young to sign back due to motor skill limitations and an undeveloped long term memory, this is still a great time to introduce signs and brush up on the mechanics of signing. Spend your time learning the theory of baby sign language, presented in this book, and perusing the baby sign language dictionary. If you re-read the dictionary through a few times, you’ll be surprised how many signs you’ll recall.
6-8 months: Your baby is nearing the time where he can make signs on his own or might even, in rare cases, actually be signing. Your baby’s memory is improving and is able to learn patterns in his environment. If you start signing persistently now you can expect your baby to sign back in about 2 months.
8-10 months: Your baby’s fine motor skills and coordination is improving dramatically at this stage and pretty soon he’ll be ready to start signing. Signs at this stage, if done by your baby, will be simple, but in this window, it’s entirely possible for him to understand the meaning behind them. If signing is introduced right now, you can expect your baby to sign back within 6-8 weeks.
10-12 months of age: When most babies can be expected to make their first signs and an excellent time to begin your signing program. If you start your signing program at this stage, your baby will likely sign back in 2-3 weeks. The more persistent and aggressive you are with your signing program will determine how fast you can get baby to sign back.
12-18 months of age: When babies should be expected to flourish and add many signs quickly and also a time when babies can combine multiple signs. If you haven’t yet started to sign, go for it, it’s still not too late. Your baby is becoming more verbal near the end of this age, but signs will still be their primary method of communication for some time yet.
19-36 months of age: A time when baby is becoming more verbal and dropping signs in favour of words they can easily say. However, your baby will likely continue signing with some words especially when they need to clarify or wish to add emphasis to certain messages. Any new signs can be reproduced by your baby almost instantly. More complex signs can be introduced and signed sentences will begin to appear.