A quick review of the differences between Eastern & Western Armenian.
There exists a division in the Armenian language. Like many languages of the world, geography and the events of history have shaped this language, dividing it up into hundreds of dialects. Every one of these dialects spoken today falls under one of two categories: Western Armenian or Eastern Armenian.
is spoken throughout much of the Diaspora, including, but not limited to, Lebanon, Syria, Iraq, Egypt, Ethiopia, Turkey, Australia, Europe, North America and South America. It was developed in the early part of the 19th century, and is based on the Armenian dialect of Istanbul.
is spoken in the Republic of Armenia, Nagorno-Karabagh, Georgia, and the Diaspora in Iran. Because of the recent migration of Armenians from Armenia and Iran to the rest of the world, Eastern Armenian is becoming prominent in what used to be exclusively Western Armenian strongholds. Like Western Armenian, Eastern Armenian was also developed in the early part of the 19th century. But unlike Western Armenian, it was based on the dialect of the Ararat district of Russian Armenia. Both dialects are a mere 200 years old, which means there was no official division of the language before this.
The oldest known form of Armenian is Classical Armenian. It was first written down using the Armenian alphabet in the year 405 AD. All Armenian literature up until the 18th century was written in Classical Armenian. It is still the liturgical language of the Armenian Apostolic Church. Many Greek, Persian, Hebrew, Syriac, and Latin manuscripts survive only in their Armenian translation. Classical Armenian is also important because it preserves many archaic features of the Proto-Indo-European language. The importance of this ancient language should not be underestimated. What Latin is to Italian; Classical Armenian is to Modern Armenian.
Now let us compare both dialects of Modern Armenian to Classical Armenian. The phonology of Eastern Armenian preserves the Classical Armenian three-way distinction in stops and affricates: one voiced, one voiceless and one aspirated. This means that every single sound which exists today in Eastern Armenian existed in Classical Armenian. Eastern Armenian preserved the sound of each individual letter. Western Armenian has kept only a two-way distinction: one voiced and one aspirated. Eastern Armenian has 31 distinct consonantal sounds, whereas Western Armenian has been reduced to 24. This is the main reason why people from the two dialects have trouble understanding each other. Examining some loan words will make things more clear. The name Daniel, which is pronounced that way in Classical and Eastern Armenian, turned into Taniel in Western Armenian. Abraham turned into Apraham. Germania turned into Kermania. Italia turned into Idalia. America turned into Ameriga. It should be mentioned that both Eastern and Western Armenian use the same alphabet. Both use the same letters, but it is the individual pronunciations of those letters which are different.
Furthermore, during the 1920s, after Armenia joined the Soviet Union, there was a reform in the orthography, or spelling structure, of the language within the Armenian Republic. In order to rapidly increase the literacy rate, many languages within the Soviet Union, including Armenian, became simplified. This reformed orthography is still the official diction of the Republic of Armenia. However, it is barely practiced outside of Armenia. The Diaspora kept the traditional, classical orthography known as Mashdotsian Orthography. It is interesting to note that the Armenians of Iran are the only ones who kept both the phonology and the orthography of Classical Armenian.
Both Eastern and Western Armenian are the offspring of Classical Armenian, but the phonology of Eastern Armenian lies more closely to that of Classical Armenian. Speakers of Eastern Armenian properly pronounce each individual consonant of the alphabet. Speakers of Western Armenian do not use 7 of the 31 consonants used in Classical Armenian.
The Armenian Alphabet այբուբեն in English Aybuben as Eastern Armenians write or Aypoupen as Western Armenians do.