Greek alphabet
Another diacritic is a comma, usually above initial vowels. This signaled whether or not the sound of the letter 'H' was present. It is not available in the English standard character-set.  If this comma-like diacritic above the vowel is reversed, it indicates the presence of an /h/ sound before a vowel, diphthong, or rho. Thus, the Greek name Ἕκτωρ is pronounced Hektōr, not Ektor. Another example is ἥρως, pronounced hḗrōs ("hero").