Gwoyeu Romatzyh
Other means of indicating tone in romanization include diacritics, tone letters, and orthographic changes to the consonants or vowels. For instance, in Mandarin, the syllable (which has a falling-rising tone) is represented in Wade-Giles romanization as "ma3", with a tone number; in Hanyu Pinyin as "mǎ", with a diacritic; and in Gwoyeu Romatzyh as "maa", with a change in the vowel.