Actually, the Honda Accord Euro R ~= TSX. I don't know what the TL is called in Japan. HSC is a concept of the next-gen NSX, but the NSX is being discontinued worldwide. The RDX is also a concept. There would be very little market in Japan for a luxo-SUV such as the MDX.

America gets a short little title like RSX or TL because to Americans, that sounds upper class and sophisticated. Which Acura is meant to be. In Japan, there is no Acura, only other Honda models. Japan-model cars have English titles because they sound cool to the Japanese public. Titles like Celica, Supra, and Integra are all based on American words but just sound cool.