The latin alphabet was designed for atonal languages. When you need to also indicate tone, you've gotta put the marks somewhere. You could do a lot worse than d

The latin alphabet was designed for atonal languages. When you need to also indicate tone, you've gotta put the marks somewhere. You could do a lot worse than diacritics whose shape roughly reflects a graph of pitch over time. (In Mandarin, pinyin uses diacritics that exactly graph pitch over time. Very helpful.)