If my memory is correct, Henry was born speaking in sentences. I hate when parents brag about stuff like that, but it's a fact: Henry's a fantastic talker.
Jane's vocabulary hit a plateau about four months ago. She speaks about as well at 20 months as Henry did at maybe 10. However, she communicates almost as well as he does now, thanks to some tricks she's invented.
She has mastered all the basic words (hi, bye, yes, no, Mumma, Daddy, Nenny [Henry], sorry, pease [please], that, mine, baby...). But she also has a few expressions she stretches to mean a whole lot of different things. Here are a couple of my favourite:
Oh: This can mean several things. Sometimes it's, "Well! That's new, isn't it?" Other times it's, "I accept what you're saying as true." Or, "Explain this foreign thing, please." Or, "Things aren't working out like I planned." Or even, "Leave me alone, Parent. I've got this on my own."
Mmm Hmm: This can be a simple affirmative, but more often it's an acknowledgement of understanding a new concept or a request.
Happy Daddy: This originally was Jane's version of the song Happy Birthday. It has since morphed into her catch-all phrase for almost anything to do with me. It can be as simple as, "Daddy's home!" But has been used for more complicated things like asking me how I feel about something.
She's also developed her own version of sign language which has become quite complex. In combination* with her actual words and her Jane Words, it's very effective. Here's an example:
I walk in the door from work.
Jane: (running to the door) Daddy! Happy Daddy!
Me: Yes! I had a great day! What did you do today?
Me: Did you see a baby today?
Jane: Mmm hmm. (She pauses, points in the direction of our friends' house) Oh! Oh!
Me: Was it baby Zadie? Did you go to her house?
Me: She's so nice.
Jane: (cups her hands together and slowly brings them towards her chest)
Me: Did you get to hold her?
Jane: Mmmn Hmm!
Me: Were you gentle?
Jane: (scowling a bit) Oh.
Me: Did you maybe squeeze her too tight?
Jane: Mmm Hmm.
She's so good at this, she was able to completely explain to me the process of how a work crew built a new step on our neighbours' house the other day. Without having to get Erin to clarify, Jane explained the entire process, including how she and Henry watched from separate windows through the day.
*Edit: in fairness, I should point out she also occasionally makes annoying shrieking sounds until we desperately figure out what she's trying to say.