You might just buy some manga that's in Japanese <try ebay>.
(Ones that have been professionally translated are best, so you can compare your translation with one that is definitely correct).
That's what I did.... I got a lot of Fruits Basket manga in Japanese, read the English ones, and then worked on translating the corresponding Japanese volume.
Plus, if you get a lot <with reasonable shipping>, it could end up being less than buying the English version! ^-^