* Stress or accent: Showing which syllable is emphasized in a word.
* Vowel length: Indicating whether a vowel is short or long.
* Nasalization: Showing that a vowel is pronounced through the nose.
* Tones: In tonal languages, diacritics specify the tone of the syllable.
* Other phonetic modifications: Such as changes in articulation or voicing.
The specific meaning of a diacritic depends entirely on the language and writing system it's used in. There's no single universal meaning.