In English, we form yes/no questions using words like "do" or "are" (e.g., "Do you live here?"). In Finnish, you simply attach a question suffix directly to the conjugated verb.
Because of a core Finnish rule called vowel harmony, this suffix has two versions: -ko and -kö.
Vowel Harmony
Finnish vowels are divided into three groups. Words cannot mix back vowels and front vowels. When you add a suffix to a word, the suffix must harmonize with the vowels inside that word's current form:
- Back vowels (a, o, u): If the verb form has any back vowels, use the back-vowel suffix -ko.
- Front vowels (ä, ö, y): If the verb form has any front vowels, use the front-vowel suffix -kö.
- Neutral vowels (e, i): These can mix with either back or front vowels. However, if a word contains only neutral vowels, it defaults to the front-vowel suffix -kö.
Using -ko (Back Vowels)
If the verb contains an a, o, or u, attach -ko.
Using -kö (Front and Neutral Vowels)
If the verb contains an ä, ö, or y, attach -kö. You also use -kö if the verb only contains the neutral vowels e and i.
Questions with "Olla" (To Be)
The verb olla (to be) follows the exact same pattern. For example, the conjugated forms olet (you are) and on (he/she/it is) contain the back vowel o, so they take the -ko ending.
Remember the word vai (or) from the previous lesson? It is perfect for yes/no questions where you offer two alternatives: