Somewhat. Babies do tend to learn a few signs, and it is useful when they can indicate what they need. However as soon as they learn to talk they universally forget everything. I know people fluent in sign (a large part of their job is working with the deaf), and when they sign to babies the babies are like "you idiot: I just heard you talking to someone else so don't insult my intelligence by not talking to me" The babies can't say something so complex, but you can tell from their reaction that is about what they are thinking.

Which is too bad, sign language would be useful in later life. Unless there is a deaf person in the babies life though they will refuse to have anything to do with it once they can speak.

> I know people fluent in sign (a large part of their job is working with the deaf), and when they sign to babies the babies are like "you idiot: I just heard you talking to someone else so don't insult my intelligence by not talking to me"

The way my friends have done this is to speak and sign, not just sign. I don't think any of them would've thought it was appropriate to only sign to a hearing child. The purpose was to teach them both the verbal language and a way to communicate back while they were still too young to verbalize (or, in one critical case, unable to speak due to a birth defect but were perfectly capable of hearing).

   Babies do tend to learn a few signs...However as soon as they learn to talk they universally forget everything.

This was our experience with our young child. It helped to be able to say "more" and sometimes "please" and eventually "all done" but eventually spoken words replaced this communication form. My wife and I have two semesters worth of education under Deaf teachers but have no plans of pressing further on this as a second language for our son.

> However as soon as they learn to talk they universally forget everything.

A ridiculous assertion.

My son knows quite a few signs and often uses them alongside speaking, which can really help when he's struggling to be as clear (e.g. when he's frustrated).

I use signs (not ASL) to communicate with my dog. When she was a puppy, she was having trouble learning verbal commands, so I started pairing them with unique gestures, which worked much better. Eventually, I mostly dropped the verbal part and now we just use gestures.

Her vocabulary is small (she's a dog), but we have gestures for e.g. "sit", "lie down", "stand back up", "stay", "come here", "go there", "be quiet", "show me what the problem is".

(She's a Siberian Husky)

I suspect that at least some dog owners who think they've verbally trained their dogs have actually trained them (and the dog has trained the owner in return) based on body language and gestures they don't consciously know they are making, or at best through intonation rather than actual spoken command words.

This is evidenced by the reaction a dog has when you say anything with the, "who's a good boy?!" tone. You could be saying the dog is a dork or dumb and they're just as excited. The tone and body language play a huge role.

My dog intuitively knows just about anything I could want her to do. She follows me (or my SO if they're home) rendering commands like "come" irrelevant. If I put on pants during the day, she idles back and forth between where I am getting ready and her kennel, finally opening the door herself when I'm ready to leave, then I latch the gate.

She has a pretty consistent schedule so most of the time, when we're doing something, she knows exactly what her role is. Another great example is treats. For the longest time we only made her sit to get treats, so now she basically does that. A few months ago, I wanted her to learn lie down but I paired it with sit first. So now if she hears the treat bag, she'll come over to me, wait for me to say one word, then she sits, then waits for another word, and then she lays down. However those words are meaningless to her. If I say, "Lay down" first, she sits. You get the idea!

That said, she's a great pup and very well behaved. :)

One great life pro tip is to reward Good Dog paired with a sign, e.g. "jazz hands", so if they start going deaf, they still know they are being praised.