umlaut

Linguistics The change, especially an umlaut, that is caused in a sound by its assimilation to another sound.

元变化，变：由于一个被另一个词化而导致的变化，尤其是元的变化

Guangdong romanization makes use of diacritics to represent certain vowels.This includes the use of the circumflex, acute accent, and umlaut in the letters ê, é, and ü, respectively.

这一系列的拼方案兼容性较差，只能纪录粤语、话、闽语的某几个方言点，而不能纪录这三种语言的大多数方言点。