became isolated from many of the regions of the Byzantine Empire. The Pontians remained somewhat isolated from the mainland Greeks, causing Pontic Greek to develop separately and distinctly from the rest of the mainland Greek. However, the language has also been influenced by the nearby Persian, Caucasian, and Turkish languages. Dialects Greek linguist Manolis Triantafyllidis has divided the Pontic of Turkey into two groups: the Western group (Oinountiac or ) around Oenoe (Turkish Ünye); the Eastern group, which is again subdivided into: the coastal subgroup (Trapezountiac) around Trebizond (Ancient Greek ) and the inland subgroup (Chaldiot) in Chaldia (around Argyroupolis (Gümüşhane) and Kanin in Pontic), its vicinity (Kelkit, Baibourt, etc.), and around Kotyora (Ordu). Speakers of Chaldiot were the most numerous. In phonology, some varieties of Pontic are reported to demonstrate vowel harmony, a well-known feature of Turkish (Mirambel 1965). Outside Turkey one can distinguish: the Northern group (Mariupol Greek or ), originally spoken in Crimea, but now principally in Mariupol, where the majority of Crimean Pontic Greeks of the Rumaiic subgroup now live. Other Pontic Greeks speak Crimean Tatar as their mother tongue, and are classified as "Urums". There are approximately half a dozen dialects of Crimean (Mariupolitan) Pontic Greek spoken. Soviet Rumaiic, a Soviet variant of the Pontic Greek language spoken by the Pontic Greek population of the Soviet Union. Ophitic The inhabitants of the Of valley who had converted to Islam in the 17th century remained in Turkey and have partly retained the Pontic language until today. Their dialect, which forms part of the Trapezountiac subgroup, is called "Ophitic" by linguists, but speakers generally call it . As few as 5,000 people are reported to speak it. There are however estimates that show the real number of the speakers as considerably higher. Speakers of Ophitic/Romeyka are concentrated in the eastern districts of Trabzon province: Çaykara (Katohor), Dernekpazarı (Kondu), Sürmene (Sourmena) and Köprübaşı (Göneşera). Although less widespread, it is still spoken in some remote villages of the Of district itself. It is also spoken in the western İkizdere (Dipotamos) district of Rize province. Historically the dialect was spoken in a wider area, stretching further east to the port town of Pazar (Athina). Ophitic has retained the infinitive, which is present in Ancient Greek but has been lost in other variants of Modern Greek; it has therefore been characterized as "archaic" or conservative (even in relation to other Pontic