Who's teaching Whom?

This whole language thing learning process is a mysterious and complicated thing. In fact, it raises a number of questions. Here are two I've been thinking about lately:

1. Who are the teachers, who are the learners?
Often it seems to me Jess and Eves think they are teaching us their language rather than the other way around. Let me give you an example:

I say, holding up a shoe and enunciating very carefully: "Sssshhhhooooeeee, this is a shoe." Evie watching me carefully, points at the shoe and says "Ga-ga". I say, "no, it's a sssshhhhh-ooooo! Can you say 'shoe'?" She says: "Ga-ga". I turn to Jess. "Jess, can you say 'shoe'?" He says, "ga-ga". And this isn't an isolated incident. Indeed it occurs daily--whenever we're on the topic of shoes (which we frequently are since we are constantly putting back the shoes they are constantly removing). Always it's the same. We point to the shoes, ask "what is this" and always we are instructed "ga-ga". When will we learn?

We're discovering that, with twins, language learning is a bit more complicated. They come to agreed upon meanings amongst themselves and the natives want to stick to their own language. "Ga-ga" for shoe is just one example. Here are some others:

• "baba?" while holding out an object means "do you want this?" or "baba!" again, while holding out an object means "take this!" or "baba" said while grabbing and object means "I'm taking this" (It's a general giving and receiving word.)
  

• "gub-gub" this is the word for these little notches on the side of their booster seats.

Here's a little sample of everyday experiences in communication with the little people:

2. What counts as saying a word?
If I count all the sounds they make that we can recognize as words, then I'd say they've each got between 15 and 20 words. But I must confess many of them are variations on 4 consonant sounds repeated:

• "ba-ba" (prounced with slight variation, emphasis or speed can mean either "ball", "book", "bottle", "bye-bye", "baby", or even "bear", "bubbles", "bounce" and, as mentioned previously, "want this?" or "I'm taking this".)

• "muh-muh" (depending on slight variations that only a discerning and loving parent can hear can mean: "mama", "memaw", "elmo", "more", "milk", or, if there's only one "muh", then it means "muffin")

• "ga-ga" (="go" or "shoe")

• "da-da" (="dad", "duck", or "downstairs")
  

Only clear words so far:

• "up" (but "up" means "out", "in", "on", "down"--basically its a generic preposition word) --so do I get to count it just once or do I count if for every preposition for which it is employed?
  
• 'O" (for Cheerios),
  
• "na-na-na-na" (banana)