[devilbunny]

There is a fascinating documentary about this, but I cannot recall its name. One segment talks about a form of sign that represents sound, so that the child learns their family’s language (rather than sign language, which is another language entirely). It is very unpopular in the deaf community despite its advantages for daily life.

[lazyasciiart]

Sounds like Signed Exact English, which is disliked both for the context around it and for being more awkward than a natural sign language (e.g I think it doesn’t take advantage of using positions in space for grammar, it only uses the hand shapes and movements?)

I don’t know of any language agnostic phonetic sign used as a first language for children: that sounds about as hard as making them learn through writing instead of talking.

[gugagore]

They are likely talking about "cued speech".