The Turkish language doesn’t have an alphabet of its own. In the 1920s, the establishment of the Republic of Turkey was accompanied by a language reform, which introduced a whole new alphabet based on a modified version of the Latin script.
In the Ottoman era, modified forms of Arabic letters have been used in Turkish writing. Additionally, since the early 1700s until as late as the mid-20th century, Turkish has been written using the set of the Armenian letters. This has unsurprisingly been a common practice among Turkish-speaking Armenians who had either lost their own language or found that using the Armenian alphabet is far more advantageous than employing the complicated Arabic writing.
And indeed, modern Turkish matches with the Armenian set-up much more than with the Arabic writing: both Turkish and Armenian languages featured separate letters for separate sounds and were written from left to right, while the use of Arabic implied cumbersome modifications and left-to-right writing. In the late period of the Ottoman Empire, it has been even proposed to adopt the Armenian alphabet as the official writing of the Ottoman Turkish, especially given the fact the Ottoman elite has been familiar with the Armenian writing system.
Armeno-Turkish could be described as a cultural expression rather than just a mere set of letters. After all, it is an artifact of Turkish-speaking Armenians that survived for at least one generation after the 1915 Armenian Genocide. One of the earliest novels in Turkish, Akabi Hikayesi (“Akabi’s Story”) by Hovsep Vartanian, has been written in Armeno-Turkish. Many 19th-century prayer books were published in Armeno-Turkish as well, mostly by American missionary groups, which would allow many Armenians to practice Christianity, study the Bible, and pray.
During that era and even decades after the Genocide, Armeno-Turkish newspapers were published as well. Faded signs of Armeno-Turkish can be also found in the streets of present-day Istanbul. The last Armeno-Turkish book was published in Buenos Aires in 1968.
Prior to the emergence of the Armeno-Turkish writing, the Armenian alphabet has been used during the 17th century for another Turkic language, Kipchak, which has been used in the territory now known as Poland and Ukraine. The local Armenian communities adopted Kipchak over generations and put together unique works written in Kipchak with Armenian letters. Both Armeno-Turkish and Armeno-Kipchak writing systems used the pronunciation of Western Armenian as a basis.