Japanese is a lot less cumbersome to type on a numeric keypad than English. (The common input method was that every key had a consonant and the number of times you pressed the key was the vowel. Current touchscreen input methods are very similar, using the position for the consonant and a swipe direction (up/down/left/right/none) for the vowel. Wayyyy better than having 26+ touch targets on your tiny screen for English.)