The Roman input method allows you to input the Japanese phonetics without using Japanese Kana keys by combining consonants and vowels using English alphabets. In fact, the Roman input method is more popular than the Kana input method, because if you know the positions for 26 characters, you don't have to remember 45 Kana key positions. When composing Kana characters by the Roman input methods, some characters require unique keystrokes.
When a vowel (a, i, u, e, o) or phonetics with [y] or [n] follow ん or ン, type [nn] or [n'] to compose these Kana characters.
For example, to input the word 単位 (たんい), type [ tan'i] or [tanni].
To compose small っ and ッ, repeat consonant that comes after them or type [xtu].
For example, to input the word 結構(けっこう), type [kekkou] or [kextukou].
To compose the symbol for a stretching sound, use [hyphen] key or [minus] key.
For example, to input the word コンピュータ, type [konpyu-ta].