Some words in Japanese are pronounced as having a momentary pause in air flow and these pauses are represented by a small (half-height) hiragana as shown below. These pauses are meaningful and the presence of a pause will result in completely different words. Listen to the following words.

We refer to this pause in air flow as double consonants due to the fact that when these are written in romaji, we use two consonant characters like /tt/, /kk/, /ss/, and so on (きった is written in romaji as "ki-t-ta" and きいた as "ki-i-ta"). The Japanese perceive each pause as having the same length as one "syllable." This means both きった and きいた are perceived as having three syllables and the same length.

Note that a small hiragana and a full-size hiragana are pronounced differently as shown below.

Exception: The romaji sequence /nn/ is NOT considered as double consonants, so a small is not used for /nn/. (Study how the word こんな is spelled differently in romaji from the word こな below.)