Middle Armenian

Middle Armenian (Միջին հայերէն or կիլիկեան հայերէն), also called Cilician Armenian (although this may be confused to refer to modern dialects), corresponds to the second period of Armenian which was spoken and written in between the 12th and 18th centuries. It comes after Grabar (Classical Armenian) and before Ashkharhabar (Modern Armenian).

Classical Armenian was predominantly an inflecting and synthetic language, but in Middle Armenian, during the period of Modern Armenian influence, agglutinative and analytical forms influenced the language. In this respect, Middle Armenian is a transition stage from Old Armenian to Modern Armenian (Ashkharhabar). Middle Armenian is notable for being the first written form of Armenian to display Western-type voicing qualities and to have introduced the letters օ and ֆ, which was based on the Greek letters "o" and "φ".

Additions
The letter օ, based on the Greek letter o, was added during this period. It represents the IPA sound (open-mid back rounded vowel). Although this is a native phoneme in Armenian, the sound that would usually represent it, ո, was used only in medial and final positions. Initially, ո represents. Therefore, this letter was invented to only be used in initial positions to represent the sound /ↄ/ itself. It is still used today in the Armenian alphabet.

The letter ֆ, based on the Greek letter φ, was added during this period. It represents the IPA sound (voiceless labiodental fricative), which is not a native phoneme in Armenian. However, it was prevalent in borrowed words, making it necessary to use a letter to write it. It is still used today in the Armenian alphabet.