Yes, I am a father and of course all fathers are interested in their children's development, but I'm also an educator and one who focuses on English as a Foreign Language. As such, watching the boys develop their languages has been utterly fascinating to me. Both of them started out with Japanese, in terms of actual words I mean (For babbling, they both had a much expanded 'vocabulary' over their Japanese friends, not too surprising given that English has a lot more sounds than Japanese), and for a while with both I was worried that while we were trying for bilingualism, we were getting monolingualism.
I really shouldn't have, but that part is more father than educator.
But in many ways, it's absolutely fascinating. Makoto started off with "hush" and now speaks as a normal 4-year-old, albeit one with a slightly lower vocabulary mainly because some of the items he encounters are only named in Japanese. Right now he has a set rule about what he speaks to whom. Grandma, Grandpa, and Daddy get English, Jiji, Baba, and Mommy speak Japanese. If he encounters a Western face, he switches to English without missing a beat. Admittedly, a year or so back, there was no set rule for him and he would just fling random language at people and get frustrated when Grandma had no idea what a neko was or why Baba didn't understand him when he talked about going to America.
Now, if you read up on bilingualism, it becomes apparent that the quicker you expose a kid to it, the better. And it can't be done via TV, babies want the real thing, which is why Beloved and I have set the ground rules for the boys; I speak English, she speaks Japanese. When we're together as a family, the general default language is English just because Beloved's English is far, far better than my Japanese.
So far, it's been working as Makoto can and does switch between language at the drop of a hat.
Not to say that we haven't had some problems, the damn kid is too smart for his own good sometimes and isn't above asking Mommy for something in Japanese and then turning around and asking Daddy for it in English after getting shot down.
But getting back to language development, Hikaru is current in the middle of a language explosion. After taking a long time to start, he is rapidly adding words to his vocab, pointing out very important objects like Hiro, Anpanman, cats, dogs, and telling people he wants THAT or he wants to go upstairs. He's also adding English words, wow, yeah, ok (All of which sound just like Daddy) and my favorite, Daddy.
It really is the sweetest sound a father can hear. It came as a surprise to me because the day before, the best Hikaru could manage was Dada, which wasn't bad, but he also called things on TV dada so there was some question as to if he meant me. The other day however when I returned home, it was to "Daddy! Daddy! Daddy!" and a tackle hug to the knees from a flying toddler while the four-year-old attempted to climb up my arms.
Hikaru has also very quickly picked up that, yup, saying this gets my attention, so right now I have a small person trailing behind me most of the time saying "Daddy, daddy, daddy!", but it's all good.
Until Makoto joins in. Having a stereo rendition of "Daddy!" at top volume makes me reconsider the whole project... either that, or perhaps I should just teach Hikaru how to say Mommy instead.