My DC1 was very, very articulate at 22 months too - agree with Brightandearly's commets - DC2 was born when she was 24 months, and when I think back to conversations I had with my tiny 22 month old now, as the parent of a 10 year old, 8 year old and 5 year old I wonder what I was on, but she seemed so mature as an almost big sister, and really she was in some odd ways... yet she was essentially a talking, walking, bald 4 toothed baby all the same :o
My DD was a bit freaky - her language was so good and she seemed so rational, but she was a baby... she tried to persuade me, in clear, grammatically correct, sentences, to take her foetus brother out of my tummy for her to look at, 100% convinced that my assurances that it would not be possible to put him back to finish growing were incorrect...
She also talked at length about which trees in the field behind the house liked children and which didn't...
One evening, when I was 23 months pregnant and we had just moved house, I went for a shower and she appeared at the shower door distraught, telling me that Daddy had fallen off a table while mending a light on the ceiling... I was freaked out and it was plausible he had electrocuted himself, but no... her had been on the lap top ignoring her and she had been bored and made something up to get my attention...
She was clever and articulate but utterly feral at that age :o Quite a lot of people were fascinated by her (she was also picking up a second language at a rate of knotts at that point, and by 24 months she spoke her new second language better than a lot of same age locals and better than me- but she is just very good with language, she is only very averagely rational or mature or intelligent aside from the language and imagination aspects')
DD used to climb onto the windowsills or kitchen counters or top of the bookshelves when I was BFing DC2 and shout that she was naughty and I had better put her on the step... she knew what she was doing - she wanted me to put DC2 down and put her on the naughty step; only ignoring or laughing at her worked.
On the plus side, at 2.5 she was healthy and DC2, aged 6 months, and I had a vomiting bug, and she made all 3 of us a round of jam sandwiches and brought us plastic beakers of water throughout a day at home quite confidently and competently and knew to behave and watch cbeebies and take herself to the toilet and bring me nappies for DC2 and be helpful all day because we needed that. Lots of 4 year olds wouldn't do that.
She is perfectly normal and average and logical and rational but unremarkable at nearly 11
Your DD is her own normal and will be fne, as will you. She is probably not as clever as her language is making you think though ;) ''It will all come out in the wash.