Yep we're doing it, TBH it's been more useful > 1 year than it was before then. But even so DD consistently used signs for 'booby" and "more" "hungry" and "milk" before then, which was useful at times.

Now it's great because she will see or hear something and use the sign (before she has the word for it) so we understand her in some situations when she might otherwise just be jabbering on to herself, kwim? It's fun for other family members too.

And no, it definitely does not delay speech - you speak the word every time you sign it and if anything that reinforces their spoken language skills.