Watch your pronunciation ESPECIALLY with easy words. You know, those easy English words that every Japanese person knows. For example- sorry (not ソーリー) or car (not カー）. And: dinner, dog, apple, vanilla, fish, cafe, shirt...
Foreigners in Japan who are used to heavy Japanese accents may understand you. But if you go abroad and say "シャツ" instead of "shirt," you will not be understood. When speaking English- forget katakana!
