Punctuation Marks - Σημεία στίξης
In ancient Greek, there were more than one accentmarks but in modern Greek, there is only one accent mark ( ΄ ) denoting stress. This accent mark appears in two or more syllable words above the vowel of the syllable on which the stress falls.
Vowel elision - Πάθη φωνηέντων
In some words, vowels or consonants may drop out. This can happen at the beginning, middle or end of words.