I can certainly help out as I have been in Taiwan for more than 10 years, but not Taiwanese.
What is Taiwanese language?
You may know the official language here is Mandarin. But there are other languages spoken.
Taiwanese as a language, is normally related to the dialect commonly spoken in the Fujian province of China. Fujian is located nearby Taiwan and is where many immigrants to Taiwan have come from. Taiwanese has however developed a little separately to the language now spoken on the mainland Fujian province, in much the same way American English and English in the UK are different.
There is the aboriginal Taiwanese, which make up nine main tribes and do not have Chinese ancestry, instead having Polynesian roots, these languages are not widely used at all outside of the tribes.
I would suggst going to www.forumosa.com
, you will find all answers you need regarding Taiwan there.