Jackrose, thanks for that suggestion. I'll give it a go. I actually have a book here about baby sign language.
And yes, you are right, she is incredible. And I am completely objective

It's just confusing, because she does know and uses the words for wee and poo. But not until after the fact. So the association is there, just not the timing.

By the way, DD only just learned the word for milk. And I find that surprising, because milk is like her favourite thing in the world, I expected her to learn that word much earlier (She is being raised bilingual, so I find a delay in her speech is completely normal). But she always knew how to communicate that she wanted some. At first she would stand in front of the microwave, saying "beep beep beep" because we used to heat her milk in there. Then she started standing in front of the fridge, whingeing. Until recently, she would stand in front of the fridge saying "more". Or, if I had forgotten to lock it, she would get the bottle out and bring it to me

I am glad that the signing seems to be working so well for you. Learning a different sign each day seems like fantastic progress.

Sasa