Iota: The Coptic Letter (Value 10), from Greek Iota

Iota is the tenth letter of the Coptic alphabet and the first of the tens in the numeral series, worth ten. It is a busy letter. Coptic uses it for the vowel i and also for the consonant y, a double duty it took over from Greek along with the shape, and it appears in a wide range of grammatical elements, in pronominal and possessive forms, and in the diphthongs that Coptic writes out letter by letter rather than with dedicated signs. On a typical page it will be among the commonest characters. Iota also carries one of the small scribal conventions Coptic inherited from Greek manuscript practice.

Where a word begins with iota, or where iota follows another vowel and needs to be read as its own syllable rather than as part of a diphthong, scribes wrote two dots above the letter. The device is a reading aid rather than a mark of pronunciation, and it does the same job on the Coptic upsilon. Conventions of this kind matter more in Coptic than in a language with word division and punctuation, because early Coptic manuscripts are written in continuous script with little or no space between words, so a reader depends on whatever signals the scribe chose to supply. The superlinear stroke marking a syllabic consonant belongs to the same family of aids.