[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".