With the advent of Roman type it was reduced to the round dot we have today.), were used to mark pitch accents in Hangul for Middle Korean.
They were written to the left of a syllable in vertical writing and above a syllable in horizontal writing.
Other letters modified by diacritics are treated as variants of the underlying letter, with the exception that ü is frequently sorted as y.
Languages that treat accented letters as variants of the underlying letter usually alphabetize words with such symbols immediately after similar unmarked words. in phone books or in author catalogues in libraries), umlauts are often treated as combinations of the vowel with a suffixed e; Austrian phone books now treat characters with umlauts as separate letters (immediately following the underlying vowel).
In the Hanyu Pinyin official romanization system for Chinese, diacritics are used to mark the tones of the syllables in which the marked vowels occur.
In orthography and collation, a letter modified by a diacritic may be treated either as a new, distinct letter or as a letter–diacritic combination.
Vowel pointing systems, namely the Arabic harakat ( ), which, respectively, mark abbreviations or acronyms, and Greek diacritical marks, which showed that letters of the alphabet were being used as numerals.
Diacritical marks may appear above or below a letter, or in some other position such as within the letter or between two letters.
The main use of diacritical marks in the Latin script is to change the sound-values of the letters to which they are added.
The South Korean government officially revised the romanization of the Korean language in July 2000 to eliminate diacritics.
Different languages use different rules to put diacritic characters in alphabetical order.