Mother Tongue?

In Cambridge Dictionaries Online:

mother tongue:
the first language that you learn when you are a baby, rather than a language learned at school or as an adult

In Oxford English Dictionary:

mother tongue:
One's native language; a first language. Also in extended use.

So, what is my mother tongue? Chinese or Taiwanese?

I was filling out the form for applying Fulbright Scholarship and got confused what exactly my mother tongue is. It's in the language skill section. In addition to my mother tongue, I should list other languages that I'm familiar with and evaluate myself in three aspects: reading, writing, and speaking. Of course I should list English otherwise I have no chance to win the scholarship :P

I evaluate myself in English with excellent reading, good writing and fair speaking. It's somehow NOT true. I wonder if I'm that good XD At that moment, it occurred to me that I've learned English about 16 years!!! 2/3 of my life!!! And it's gonna be more... I started learning English in my third grade that I went to Sesame Street. I finished almost all the courses but sadly the extension school went bankrupt right before I could have the certificate. After then were 6 years of high school (junior high and senior high) formal English education. In college (undergraduate and graduate), I took in average 2 credits of English courses yearly, which is very very ... very little amount. However, thanks god that I'm in love with American TV serious so that I can still be friend with English through entertainment. However however... 16 years of English learning seems not working well to me :P I have little vocabularies, I read slow, I write with errors, I listen but can't understand completely, and I can't even speak to people oQ_Qo

Well... back to the target, what is my mother tongue? Taiwanese? Somehow, Yes! When I was a little girl, I spoke Taiwanese to my grand-mom, mom, dad, and elder brother. I couldn't even understand Chinese that I elder brother spoke Chinese, which he learned from school, to me and I cried to ask my mom what he said. Actually, I don't remember all these. My mom told me :P

Nevertheless, after I went to school (4 to kindergarten), I gradually forgot how to use Taiwanese. Onetime, I couldn't even distinguish toothbrush from toothpaste. Now, when I talk to my parents, I use Chinese and they use Taiwanese. It's kind of interesting XD


Regardless of all these, what I'm in trouble with is that if I list Chinese as my mother tongue, then I have to evaluate my reading, writing, and speaking abilities in Taiwanese. It's crazy hard. I don't even read and write Taiwanese!!! There are words in Taiwanese of course, but common people seldom use them. Taiwanese is generally used to speak rather than to write. Therefore, according to the definition of mother tongue and to resolve my dilemma, I should list Taiwanese as my mother tongue. Then, I can evaluate my Chinese with excellent reading, excellent writing, and excellent speaking!!! Sounds pretty good XDXDXD