Margaret knows about three words - "ma" (or "mamamamama") for mom, "da" (or "dadadadada", sometimes substituting the Chinese "b" for the western "d") for dad, and "nai" (or "nanananananana") for milk/formula. (Note that "na" is repeated the most times, as it's the most important word.)
She doesn't use the words to communicate, though. Rather, she generally uses the words to express her feelings. "Mamamamama" doesn't mean "take me to mommy, immediately"; it means "I miss mommy and wish she were here". After all, how much can one communicate with only nouns and no verbs?
Rather, to communicate, she uses actions. This morning, during the hour I was with her, was a particularly good example.
First, daddy got confused during the handoff and thought mommy was going to bring some formula up before going to work, so he left the door to the play room open. After a while, when Margaret heard some sounds from downstairs, she started crawling tentatively towards the door. She knows she's not allowed to crawl past it, though - the top of the stair is there - so when she got to the threshold, she looked straight at me and raised her arms into position to be lifted by an adult: "pick me up!" See how much easier it is to express verbs and imperatives in gestures rather than in words?
After a visit downstairs confirmed that the noises were, in fact, mommy, but that she just needed to check her email before work, we went back upstairs. After a bit, there was a baby poop smell. When daddy didn't do anything immediately - we generally wait five minutes since there's often a follow up - Margaret crawled over to the end of the couch where the bag of diapers are usually kept. The bag was missing though - unbeknownst to her, the bag had been emptied earlier when her evil twin decided that the diapers needed to be strewn all about the floor, and a parent had picked them all up and put them out of reach - so after a moment's consideration, she grabbed the bag of wipes and tugged at it repeatedly, in a "daddy, don't you know what these are for?" way. The message was clear.
The last one was the most inventive. The newly clean baby dropped down off the couch and picked up the bottle of baby powder, raising it and crying repeatedly. Maybe it's supposed to be stored on the couch? Daddy picked it up and put it on the couch. But no, Margaret asked for a lift onto the couch, then grabbed the baby powder bottle again. Then she started alternately shaking it and sucking at the top. "Daddy, what comes in a bottle that gets shaken up and then sucked on?" Yes, formula gets shaken up to mix it - something Margaret likes to help with - and of course is drunk from the bottle. Sometimes you have to paint a very clear picture for that slow daddy to understand!
We should have, but we were too lazy (or at least I was). Maybe I'll try a few based on chenoameg's recommendation. Thus far, she's been putting the cap back on the bottle to indicate "finished", but that may be subject to misinterpretation - if she doesn't recap the bottle when it's empty, does that mean "it doesn't need a cap, it's already empty, silly daddy", or "I'm not done yet"?
Hm, squeezing on the nipple may have been more than play, too - "daddy, it's empty, see how only air comes out (hint, hint)?" Daddy needs to pay better attention.
Which reminds me, the look of horror when daddy accidentally knocked the bottle over while putting her in a good drinking position was incredibly cute. Fortunately we got no-spill baby bottles.