a dental. Thus, the clusters are allowed. Certain stop clusters do not occur as onsets: clusters beginning with a dental and ending with a labial or velar, and clusters of stops that disagree in voice onset time. Coda In Ancient Greek, any vowel may end a word, but the only consonants that may normally end a word are . If a stop ended a word in Proto-Indo-European, this was dropped in Ancient Greek, as in (from ; compare the genitive singular ποιήματος). Other consonants may end a word, however, when a final vowel is elided before a word beginning in a vowel, as in (from ). Accent Ancient Greek had a pitch accent, unlike the stress accent of Modern Greek and English. One mora of a word was accented with high pitch. A mora is a unit of vowel length; in Ancient Greek, short vowels have one mora and long vowels and diphthongs have two morae. Thus, a one-mora vowel could have accent on its one mora, and a two-mora vowel could have accent on either of its two morae. The position of accent was free, with certain limitations. In a given word, it could appear in several different positions, depending on the lengths of the vowels in the word. In the examples below, long vowels and diphthongs are represented with two vowel symbols, one for each mora. This does not mean that the long vowel has two separate vowels in different syllables. Syllables are separated by periods ; any sound between two periods is pronounced in one syllable. (long vowel with two morae): phonemic transcription , phonetic transcription (one syllable) (two short vowels with one mora each): phonemic transcription , phonetic transcription (two syllables) The accented mora is marked with acute accent . A vowel with rising pitch contour is marked with a caron , and a vowel with a falling pitch contour is marked with a circumflex . The position of the accent in Ancient Greek was phonemic and distinctive: certain words are distinguished by which mora in them is accented. The position of the accent was also distinctive on long vowels and diphthongs: either the first or the second mora could be accented. Phonetically, a two-mora vowel had a rising or falling pitch contour, depending on which of its two morae was accented: Accent marks were never used until around 200 BC. They were first used in