Speech Development

I recently found out from the preschool that my daughter isn’t keeping up with the other kids with her speech development.
This came as quite a surprise, as although her speech is a bit garbled, due in part to being a kid, but also as she currently has a case of ‘glue ear’ so she’s not hearing things quite correctly; she is normally quite a chatterbox at home, and her talking away has been noted by both sets of grandparents.

The preshcool folks have apparently seen her talking to other kids, but she doesn’t chat with them.

So the options, as far as I can see here are:

1. With all the other kids at preschool, she’s just not as clear as a quiet home environment.
2. She’s a quiet kid at ‘school’, so simply doesn’t want to talk to everyone
3. Something else, developmental or hearing related.

…or even worse: Its my/our fault …somehow.

I’ve been learning British Sign Language (BSL) since she was very small, as we had been using Makaton sign with her since before she could speak at all.
Part of me wonders if this is actually slowing her down now.
She signs very well for a 2.5 year old, as far as I can tell as a learner myself - she keeps up with me at full speed at least, and responds in kind, but is that just that she’s focussing on this because its what we do rather than her speech itself?

Have I slowed her speech development?

Its probably nothing.
Probably.
But I have to assume the worst because anything else might be a disservice to her later down the line; so now we’re actively encouraging her to speak up, speak clearly and to talk with her ‘teachers’ at the preschool.

They’re working with her too, doing 1:1 sessions, reading with her, and so forth to see how she responds.

But for now; I think I’m going to put this into the ‘deep dark fears’ pile.

She’s my first (and currently only) kiddo, so all of this is entirely new to me, so everything is doubly terrifying whenever anything going wrong.
I’d love to be the kind of chilled-out parent that can just float through doing all the right things at all the right times, but I’m also nearly convinced that they don’t actually exist.

Finally a word of advice for new parents - don’t take the books to heart; I’m entirely convinced that the people who write those things are essentially outliers with specific problems, rather than the average case.
That isn’t to say that the books are useless, just that you need to take everything they say with a pinch of fiction; every kid is different, so the books are going to only be of passing relevance.
Maybe some parts map perfectly onto what you’re seeing with your kids, but that doesn’t mean everything they say will be correct.