Bilingual baby torture

I studied foreign language acquisition, bilingual children, teaching methods, etc. I'm perplexed by my daughter's preference for English. She hears French all day, with the majority of her family and my friends, with her father. Yet, I've only heard her say 3 words in French.

Our wonderful nanny says she speaks only in French during the day but I have my doubts since one day I went to get Suzanne and she was saying water and making the sign for it. The nanny told me she'd been doing that all day and thought she was teething. I said that no, she was asking for water. We gave a complete list of Suzanne's vocabulary to the nanny, but we can't expect her to understand Suzanne's version of English if she doesn't understand the language. So I was thinking that maybe she speaks English when I'm around?

But on Saturday, we lent Suzanne to her French grandparents so we could work in our money pit and all they heard from her was English. But I wasn't around so maybe she speaks English when she associates people with me?

I wonder what other bilingual kids do. Do they tend to prefer the mother's language even when it's the minority language? Maybe, quite simply, it's called a mother tongue for a reason...

At 16 months, Suzanne is very verbal (see word list below). Favorites at the moment are bath, brush, taxi and eyes. Jerome and I particularly like "eyes" because we get her to repeat it over and over and she crawls through the apartment saying "ass ass ass". Is that mean?

She's so close to walking. She's even taken a few steps without realizing what she's doing. Note to grandma - make sure anything fragile is out of reach and all cupboards are locked when we're there.

So here's the list:
taxi - more like "gacky". The New Yorker in me is oozing with pride.
yeah - she punctuates all affirmative sentences and questions with "yeah". I'm wondering if I say it too much.
bath - the "th" is somewhere between an f and an s but close enough
eyes - sounds more like ass but she's got it.
mommy - when my mother left in August, she reverted to mama but she now consistently calls me mommy as part of her string of names for me : mama mamou mommy...
knee- she's reconfigured my anatomy and thinks my knee is in my shin but that's ok.
bus - the repetitive singing of "wheels on the bus" finally paid off last week when we took the bus a few times. Now she says bus - with a proper s at the end - when we pass the bus stop.
blocks- sounds like bus
box-a slight variation of the above
go - I've played "stop and go" with her in the stroller for months and she's finally understood it.
bee - perfect pronunciation on this one!
boot/boat - she doesn't quite have the ending of either word, but she distinguishes between the hard o and the soft o
key - she always wants my keys when I let us in and she's finally asking for them with the right word
yes - she understands and repeats it but has yet to use it.
dance - she bops her head and bounces on her knees as she says "da"
down-when she wants to get down from the bed or her high chair she says "dow"
eeyah- her word for cat also means home.

She repeats a lot of words back like tushy, gassy (made me chuckle), mouth, grass but doesn't use them yet.

She's consistently identifying circles, squares and stars.

She can name family members in her photo album and in person: tonton, bopi, nanne (used for most female relatives named Anne or similar) and baba.

She's following directions like looking up at the tree or under the bed for the cats or giving a leaf to papa. And we've made a huge step in her shopping etiquette - she's finally understood that she has to give the leek to the cashier so we can pay, all without crying or screaming.

Her new animal sounds are :
pig -she's finally got some sort of throaty grunt going although it's far from a snort
guinea pig - this one's close to my heart since I had a few as a kid. So far it's more of a grunt than a proper wheek (in case you're wondering what they say...)
bee - they obviously say"beeeee"
bear - they don't growl but say "beh"
meow- she's finally realized cats, with the exception of our own, don't say eeyah.
birds - except for pigeons and owls, they all say caca
dog - is sounding more and more French

She's using a dozen signs from American Sign Language. A friend lent us a couple of Signing Time dvds. We were skeptical at first but she uses them regularly, with both us and the nanny. Of course, it would be helpful if she could sign things she didn't know how to say.