Codex, p. 60
I will give the specific quote from the original text, which appears to be slightly changed []:

Τον ευλογημένον Ζαχαρίαν τον διεδέχθη ο Άγιος Γεννάδιος. Ύτος ήτο Σμυρναίος και αυτός αρχιδιάκονος του Ιωαννίνων, νέος τη ηλικία δεν είχεν ευχαρίστησιν να ακούη χριστιανούς να ομιλούν την αλβανική γλώσσαν. Φιλοδίκαιος όλως πολλά. Αρχιεράτευσε χρόνους είκοσι πέντε. Έπειτα μην υποφέρων την αλβανικήν γλώσσα εις τα χωρία της επαρχίας του ευχαρίστως έκαμε την παραίτησιν και αφήσας...

The text added in the article translates this entry as: In an ecclesiastical entry .... noted that some of the Christian Greek clergy had linguistic difficulties in administrating to their congregation, as Christian villagers living within the region of Delvinë were Albanian speaking.

It's hardly enough from the original text to conclude that the villagers were in general monolinguals, indeed it claims that Albanian speech was present and in significant numbers (it doesn't also conclude that all villages were Albanian speaking). Moreover, the fact that this produced linguistic difficulties in eclessiastical administration is something that only indirectly can be concluded, since the Codex mentions that "a specific bishop, who came from Smyrna, found it not pleasant to hear his flock speaking Albanian, beacause of the Albanian speaking villages in  his periphery, and resigned after 25 years of local service."