The Apple Support Communities are an international user to user technical support forum. As a man from Mexico, Spanish is my native tongue. I do not speak English very well, however, I do write in English with the aid of the Mac OS X spelling and grammar checks. I also live in a culture perhaps very very different from your own. When offering advice in the ASC, my comments are not meant to be anything more than helpful and certainly not to be taken as insults.
The dictation feature is part of Siri. Siri is still a beta program which is limited to supporting these languages; American, British and Australian English, French, German and Japanese. The dictation feature is not able to understand folks who may speak with an accent outside of these parameters.