Xiamen dialect and Taiwanese has less difference between each other unlike British and American English has the great difference between each other.
Taiwanese is originated from Xiamen dialect and Taiwanese people don't need to do any translation works and they can understand Xiamen dialect as just like Americans understand British English without translation.
So, why shall "Xiamen dialect" be called "Taiwanese"? and why not "American English" being called "Americanish"?
Here is a link to a radio broadcasted in "Xiamen dialect "
http://big5.am765.com/mnradio/jmyg/z7/200709/t20070909_286666.htm?type=1
Also it makes sense that Taiwanese can be called "Min-nan" dialect or "Hokkien", but it doesn't make any sense that it is called "Taiwanese" because "American English" is not called as "Americanish"
Historical background of Taiwan:
Taiwan was also historically a part of Fujian Province(
http://en.wikipedia.org/wiki/Fujian) of mainland China from the year 1684 to 1887. In 1877 , although Taiwan was a single province ,her official name was "Fujian's Taiwan Province"(福建臺灣省).
The ancestors of the most Taiwanese residents were from Xiamen City(http://en.wikipedia.org/wiki/Xiamen) and the dialect spoken by most Taiwanese residents is "Xiamen dialect"(A dialect spoken in Xiamen(http://en.wikipedia.org/wiki/Xiamen) ,Quanzhou(http://en.wikipedia.org/wiki/Quanzhou),Zhangzhou(
http://en.wikipedia.org/wiki/Zhangzhou)cities in China,Taiwanese ppl call "Xiamen dialect" as "Taiwanese" or "Minnan dialect"(Minnan means "the southern part of Fujian" in Chinese)
During Chinese Civil War from the year 1945 to 1949 , most parts of mainland China were liberated by Communist-led "People's Liberation Army", and Chiang Kai-Sheik forces only remained parts of Fujian Province and Taiwan islands.
In history , Germany were divided into West and East Germany(DDR), and in reality, mainland China and Taiwan are as "Big China" and "Small China"
Recent Taiwan's society:
The numbers of Taiwanese students studying in mainland China's universities have surpassed the numbers of Taiwanese studesnts studying in USA since 1999.(Because of no problem of communication in language(they speak same language)for Taiwan's students in China and the cheap school expense and worth studying
Having all those Taiwanese studying in China, doesn't China worry they might pose a security threat? I suppose they keep a close watch on them. How many mainland Chinese are permitted to study in Taiwan, is it a comparable number?
Also, are Taiwanese speakers able to understand the Hokkien spoken in many parts of Malaysia, and converse fluently with them in that dialect without resorting to chinese i.e. mandarin?
Is the Hokkien in Malaysia at a more "advanced" level, because from what I gather, they actually use that as a medium of instruction in schools alongside mandarin...
Maybe Taiwan, Malaysia should unite in some kind of hokkien speaking commonwealth, lol !! They are like cousins, separated only by historical accident... borneo, taiwan... two islands in close proximity and with similar cultures...