Japanese has five vowel sounds that can have two different lengths. They are "a, i, u, e, o". In IPA they are transliterated as /a/, /i/, /ɯ/, /e/, /o/; and they are pronounced in English as "ah, ee, oo, eh, oh". Lengthening a vowel can change the meaning of the word: "ojisan" (おじさん, uncle) and "ojiisan" (おじいさん, grandfather). Japanese has a sound that is like the English "l", but it is also like the English "r". (That is why it can be difficult for many Japanese when to learn to make both sounds when they speak English.) Japanese has a sound that is not uncommon in English and is usually written "Tsu" (つ). This sound appears in "tsunami" (つなみ), the Japanese word for large ocean waves caused by earthquakes or extreme weather.