phonemes of standard Attic are unmarked, allophones are enclosed in parentheses. The sounds marked by asterisks appear in dialects or in earlier forms of Greek, but may not be phonemes in standard Attic. Stops Ancient Greek had nine stops. The grammarians classified them in three groups, distinguished by voice-onset time: voiceless aspirated, voiceless unaspirated (tenuis), and voiced. The aspirated stops are written . The tenuis stops are written , with representing lack of aspiration and voicing, or . The voiced stops are written . For the Ancient Greek terms for these three groups, see below; see also the section on spirantization. English distinguishes two types of stops: voiceless and voiced. Voiceless stops have three main pronunciations (allophones): moderately aspirated at the beginning of a word before a vowel, unaspirated after , and unaspirated, unreleased, glottalized, or debuccalized at the end of a word. English voiced stops are often only partially voiced. Thus, some pronunciations of the English stops are similar to the pronunciations of Ancient Greek stops. voiceless aspirated t in tie tenuis t in sty tenuis, unreleased, glottalized, or debuccalized t in light partially voiced d in die or Fricatives Attic Greek had only two fricative phonemes: the voiceless alveolar sibilant and the glottal fricative . is often called the aspirate (see below). Attic generally kept it, but some non-Attic dialects during the Classical period lost it (see below). It mostly occurred at the beginning of words, because it was usually lost between vowels, except in two rare words. Also, when a stem beginning with was the second part of a compound word, the sometimes remained, probably depending on whether the speaker recognized that the word was a compound. This can be seen in Old Attic inscriptions, where was written using the letterform of eta (see below), which was the source of H in the Latin alphabet: Old Attic inscriptional forms , standard ('faithful to an oath') , standard ('sitting beside, assessor') , standard ('let him be present') ('yay!') ('peacock') was a voiceless coronal sibilant. It was transcribed using the symbol for in Coptic and an Indo-Aryan language, as in for ('of Dionysius') on an Indian coin. This indicates that the Greek sound was a hissing sound rather than a hushing sound: like English s in see rather than sh in she. It was pronounced as a voiced before voiced consonants. According to W.S. Allen, zeta in Attic Greek