Just capturing a bunch of things Sophie currently says and how she says them:

• "Why?"  of course, this one needs no explanation, other than it is relentless and then followed up by ...
• "And then what would they say?"  This can come after just about anything and is by far the most common thing I hear after "Why?".  I've gotten so tired of it and trying to come up with something that I frequently will just turn it around and ask, "what do you think they would say?"
• "What happens if we don't?"  Not sure where this came from, but it's also very difficult.  "What happens if we don't pay the money at the grocery store?"  And if you just say, "well, we have to," she will always escalate the intensity, "But what happens if we DON'T?"  Again, I've found, just ask her what would happen, and then she will calmly say, "then we don't get to keep the groceries."
• "Daddy/Mommy, did you do X when you were a little boy/girl?"  Like, go to the library, fly on an airplane, etc.  "Did your mommy take you to the library when you were a little boy?"  This is my favorite thing on this list.  
• "What's dead/alive?"  She has struggled the last few months to figure out mortality, but I'm not sure she really gets it or that we've done a good job explaining it.  The last person we really know that died was my Grandmother, but while Sophie remembers great grandma and we have pictures of them together, she was too young to remember or understand the funeral.  She is also (understandably) very curious about Stephanie's daddy, who passed away in 1997.  Trying to explain that about someone she never met is even harder.  
• "I want more X!  NO NO NO I WANT MORE"  The last few weeks she has been very quick to tantrum about something ending too soon: a video, therapy, storytime, etc.  There will instantly be flopping on the floor, kicking of legs and yelling.  Like after her 5 stories are over each night, which is the same amount she's gotten for years, "I want more!  I want more stories!"
• "What's your mommy's mommy's name?"  Or any combination of long-lost relatives names'.  Naming of people's relatives seems to be kind of a fallback topic when she doesn't know what to say.  We may be in the middle of therapy and she will ask, "What's your mommy's name?"  If the therapist actually answers, she'll just move on to the next one.  We're not sure if it's some kind of OCD thing, just trying to figure things out, one of the reliable ways she's found to make conversation or what.
• "Well... how was your meeting?"  Like if I go out to a meeting and she doesn't see me until the next day, at some point, she will remember to ask me this.  There's always a very big pause after the "Well..."  It's clear that she's trying really hard to replicate that question and .
• "I'm Pablo's baby sister.  Goo goo ga ga!"  (Pablo is a character off The Backyadigans cartoon and is either a penguin or kangaroo, I can't keep them straight)  Anyway, this one is clearly a response to having a baby in the house who gets a lot of attention.  
• Marriage, weddings, brides, grooms.  Ever since we attended a wedding in July for my cousin's daughter, Sophie has been very into weddings.  She puts a blanket over her head and is the bride.  (Stephanie and I have to hum, "Here comes the bride" for her).  She has a bunch of toy rings and they are the rings.  Potato head characters get married.  Dolls get married.  She talks about when you get married you move out of your mommy and daddy's house.  When did we get married?  Talking about our wedding pictures on the wall (still need to show her the album).  She's going to marry Pablo.  Am I a groom.  Can she marry me? (No, I already have a wife.)  Are she and Peter going to get married (Not to each other.   Because that's the rules, that's why.)  
• Old Maids.  We got an Old Maid Animal card game (the Old Maid card is an orangutan with lipstick and a flowery hat on) from Braums the other day.  She asked me what's an Old Maid.  I never realized how politically incorrect this game is now.  I said it's an old lady who's not married.  Of course you don't want to get stuck with the Old Maid card.  At supper last night she blurted out "Is Ms. Angie an Old Maid?"  That's one of her therapists.  Luckily, she hasn't asked anyone that outright yet.  I guess we should talk about it before she does.  
• "I'm Tasha's twin sister."  (Tasha is another Backyardigan.)  And just a lot of talk about twins in general.  Anyone who's a brother and sister, she will ask "Are they twins?" even if one's a baby and one's like 10 years old.  It's taken a lot of reinforcing the idea that you need the same birthDAY (not just age) and same mommy.  The funny thing is that she doesn't really talk about the twins (my brothers, some sisters at her school) that she does know.  And we haven't got into the idea of identical vs fraternal yet.  
• "What's married?"  "What's a present?"  "What's happy?" "What's *any word*?"  Frequently these are things she already knows the answer too.  Sometimes I will say, "You know," and she will say.  I tell her sometimes that if she already knows the answer, she can just tell me a sentence instead of asking.  Or if it's something extra silly, like "What's a present?"  I will say, "That's the silliest question all day!"

I'm sure there's more that I forgot to list.  We are VERY VERY VERY excited about how much talking Sophie is doing now.  It is difficult for us sometimes that her speech and thoughts are so awkward, but it is improving all the time.  And we know that it's just her trying to learn how to communicate and relate to people, so we are very happy with all of it.