Thinking about having my son see a speech therapist

Ki

He used to say “mama” “dada” “banana”. But now it’s just “ah”. He can sometimes say banana, but not really. We’ve been working with sign language to help him still be able to communicate, which has helped, but it’s like he’s given up on trying to talk.

He’s showing a lot of signs of speech delay, like only understanding what I’m saying if I use hand symbols/signs, he’s not engaging with others, (I’m not sure if that’s because we haven’t socialized him enough). Has anyone else seen a speech therapist for their child? I don’t even hear baby babble. Just grunts and “ah”