The session on "Slavic dialects of Greece" includes a four page presentation by Leonidas Empirikos (son of the surrealist writer), reporting on a survey he did with Lambros Baltsiotis on the geographical distribution of Slavonic in present-day Greece. Trakatroukika is mentioned on p. 155. I give the citation here, because Kızderbent turns out not to be the only settlement of Slavonic speaking refugees to Greece:
I should also note that this is a large contiguous region [where Slavonic is spoken]; by that I mean that it is a continuous population of rural origin, to this day. A survey of Slavophony in Greece would not be complete without mentioning at least five special cases:
- The Slavonic-speaking Muslims of Western Thrace, who were not subject to the population exchanges and are called Pomaks;
- A few people in some of the Nestus villages of Stavroupoli, Xanthi;
- The "Trakatroukides" with refugee origins (Slavonic-speakers from Nicomedia in Asia Minor, settled here and there in various regions of Greek Macedonia and Western Thrace);
- The few Slavonic-speaking Patriarchists from Eastern Thrace who chose to settle in Greece;
- Slavonic-speaking Patriarchist refugees, mainly from Strumica (who settled in Kilkis), but also from Petrich, Startsevo and Nevrokop [= Gotse Delchev] (who settled in Eastern Macedonia, from New Petritsi/Veterna to Drama, Iraklia and Prosotsani).
View Greek Slavophone refugees in a larger map
The last couple of populations need explanation. Modern Bulgarian nationalism started out as an assertion of ecclesiastical independence, with the establishment of an autonomous Bulgarian Exarchate within the Orthodox church. Identity in the Ottoman Empire was credal under the Millet system, and the local bishop administered the Orthodox Christians; if Bulgarians wanted to not be Greek under that framework, they had to have their own bishops. This led to contention between Exarchists, aligned with the newly autonomous Bulgarian church, and Patriarchists, remaining loyal to the Greek Patriarch.
Linguistic or ethnic identity did not necessarily align with credal identity—as in so many instances in the Ottoman Empire; so people could speak Bulgarian (or Macedonian Slavonic—or for that matter Aromanian), but be Patriarchists. I don't know of reverse cases, native speakers of Greek being Exarchists, but I wouldn't rule anything out. After all, not all the Greek-speakers of Eastern Rumelia left for Greece in 1919, either.
The dispute between Exarchists and Patriarchists turned violent in Macedonia, culminating in the guerilla conflict that Greeks call the Macedonian Struggle. But from Shishmanov's survey, the dispute had also spread to Asia Minor, with several villages reported as containing Grecomans (the Exarchist disparagement for Patriarchists: the term is intended to mean "wannabe Greeks"). We would in fact expect the dispute to have spread anywhere in the Ottoman Empire where Slavonic-speaking populations had a Greek clergy. There was no force field between Sofia and Nicomedia, to prevent people coming across to convince the locals they were Bulgarians, and not just Christians.
I think that's the subtext to surprise at Kızderbent that I perceive from the Bulgarian Wikipedia. Bulgarian researchers found out about the other Asia Minor villages in the 1860s, and went over to encourage their Bulgarian national sentiment; Kızderbent was known about in the West fifty years earlier, and a Bulgarian national sentiment does not seem to have taken root.
(Greeks reading this should not get too smug: blogger Doctor has posted at Sarantakos' blog reports from Greek officials in Eastern Thrace, annoyed that they too had to work on the locals' national sentiment, and convince the locals they were Greeks and not just Christians.)
So when time came for the population exchanges with Bulgaria and Turkey (and the preceding violence in Turkey), the criterion for who chose to go to Greece was not linguistic but ecclesiastical. Patriarchists, who were derided as wannabe Greeks, wanted to be Greeks, and chose to go to Greece. That applied to Bulgaria—Empirikos' fifth group. It also applied to settlers from Bulgaria and Macedonia in Turkey: Eastern Thrace, Empirikos' fourth group, but also the Trakatroukides, Empirikos' third group. From Shishmanov's survey, several other Bulgarian villages of Bithynia chose Greece as well, though they don't appear to have got attention.
I don't know anything about Empirikos' second group, btw, but populations did move around in the Ottoman Empire; there's a village of Albanian Christians in Serres prefecture (Koimisi, in Irakleia municipality), for example, who are refugees from Eastern Thrace—like Empirikos' fourth group. So the Stavroupoli Bulgarians would have moved there from elsewhere in the Bulgaro-Macedonian continuum.