Russian is the everyday working language in Kondopoga, while Karelian (especially Livvi Karelian, written in Latin script) is still spoken by some older residents in surrounding villages, and Finnish is understood by a minority. English is very limited, especially among older hosts at rural guesthouses and homestays, so a small set of Cyrillic-ready Russian phrases will dramatically improve any interaction, from the bus from Petrozavodsk to a homestay doorbell or a boat ticket to Kizhi.
Use this guide by situation rather than alphabetically: load the arrival card before you reach Kondopoga, the transit and boat card for the Kizhi day trip, and the dining, banya, and church etiquette cards for the slower evenings. Pronounce Russian with stress on the marked syllable and expect replies in Russian even when you attempt Karelian greetings—locals will usually appreciate the effort and switch to Russian to help you.