On another thread, someone mentioned the talking point website, so I went and had a look and it appears DD's development is completely different - no way did she know 50 words at 2 let alone use 2 word sentences, with animal sounds included there was maybe 10, and had none but animal sounds at 18months, so she was well behind there.
But now at 2.5 she has hundreds if not thousands of words, uses well formed sentences and can have a pretty genuine conversation, including arguing (e.g. "No, I don't want to tidy my toys up, I want to make a mess" said tonight) and attempting jokes, swearing in appropriate contexts etc.
Looking at the site, she pretty much meets all the description up to 5-7, she understands orange/orange and other things, asked her to get some tape a couple of months back, came back from the kitchen with a tape measure, asked again for "the other tape", and she arrived back with sellotape shortly after. Knows about sequences and does it herself (although all recent days are yesterday, e.g. "yesterday I got my hair cut" when it was 3 days ago.) She's not a 5 year old in the things she knows, but does appear to be that site for language.
I hadn't thought it was particularly unusual - although she's clearly more talkative than most of her peers, but then that's such a small set I ever meet.
So is Talking Point really a good description and we've just got really lucky with DD?