We have been teaching Tae a few signs. She has quite a few down: bath, cereal, cracker, help, hungry, fish, milk, more, shoe, sleep, thank you, water, cute, please.
Some people say that it slows speech development; others say it progresses it. Both are backed by studies. My opinion? Either way, I love her being able to tell me what she wants and my being able to understand.
Honestly, I do think it has slowed down her attempts to communicate verbally. Why work on saying it when mom already knows what you want. At the same time, it has been interesting to see the development take place. The first sign she learned was cracker. Now she says it. Granted, you may not recognize 'ckh-a-ckh-r' for what it is, but we sure do. Now that she can say it, she refuses to sign it. Additionally, I keep forgetting to look up the signs for some of her favorite foods (peach, pear, pineapple, etc). Because we haven't shown her the sign, she attempts to copy our speech pattern for the word. So would she be attempting to talk more if she didn't have the signing to fall back on? Probably. Would I be able to understand what she was trying to communicate? I doubt it (right now peach and peanut sound exactly the same). I do love how confident she is in signing. Interestingly enough, I think that confidence has passed on to her verbal skills.
Anyway. For those who may be contemplating teaching your infant/toddler sign language, here are my thoughts. In my researching the topic, there are varying ages that 'they' recommend beginning. (I know, I know. Who are 'they' and why are 'they' saying it.) We tried starting at 8 months. Nothing happened. I continued to try, off and on, for the next few months. Still nothing. It wasn't until after she turned one that she took off. Now I can show her a sign 3-4 times and she has it down.
Something to keep in mind is that often an infant/toddler will sign a word incorrectly. That is fine. You should be looking for repetition of the sign to determine what they are trying to communicate. As you figure out their signs, continue to sign it correctly to them. They will correct their signs as they get older and their coordination increases.
I could go off on this topic, more than I already have, but these are the basics according to me. Any questions or thoughts on the topic? No, I don't really expect any replies to that question, but secretly I am hoping.