We are often asked what the difference is between Traditional and Simplified Chinese and when each should be used. The short answer is: use Simplified for mainland China (PRC) and Singapore, and use Traditional for Taiwan.
However, it gets much more interesting than this. In the first place, the question should really be reexpressed as “Chinese using traditional or simplified script”, since it’s not the language which changes but the characters used. Chinese characters have evolved, quite slowly, over several thousand years. But in the 1950s the Chinese government decided to simplify a couple of thousand of the most commonly used characters – i.e. by reducing the number of strokes needed to write them.
The language itself is not affected in any way by this change, (just as writing draught or draft in English is merely a spelling convention). Simplified script has been accepted in Singapore but never in Taiwan or Hong Kong, which continue to use the traditional versions of the characters. However, most educated Chinese speakers can read texts written in both types of script, and in any case most characters are the same in both systems.
So can we just produce one Chinese translation and then write it out in two versions: one in traditional script and one in simplified? In principle yes, but in practice “Simplified Chinese” implies Chinese as used in the PRC and “Traditional Chinese” implies “Chinese as used in Taiwan”, and these are not quite the same, just as British and American English are somewhat different. So we mostly end up with two separate translations, one for Taiwan in Tradiditional script and one for China in Simplified script. So even though I started by saying the labels Traditional and Simplified refer only to the script, in fact they end up referring simultaneously to the variants of Chinese used in these places.