Questions & Answers about He eivät pyöräile tänään.
How do we get the form pyöräile from the dictionary verb?
The dictionary form is pyöräillä (to cycle). It is a Type 3 verb because it ends in two consonants plus a vowel (-llä). To make the present negative stem, you simply drop the -lä from the infinitive. That leaves pyöräile, which goes right after the negative verb.
The lesson mentions consonant gradation for Type 3 verbs. Why doesn't pyöräile change its consonants?
Consonant gradation only affects the letters k, p, and t when they are in the middle of a word (like the t in ajatella, which strengthens to tt in ajattelen). Since pyöräillä doesn't have any of those letters in the middle of the word, its stem does not undergo consonant gradation.
Why use eivät instead of ei?
In Finnish, the negative word for "not" is actually a verb that changes to match who is doing the action. Because the subject here is he (they), you must use the matching "they" form of the negative verb, which is eivät.
Can this sentence also mean "They are not cycling today"?
Yes, absolutely! Finnish does not have a separate continuous tense (like "am doing" or "are cycling" in English). Depending on the context, eivät pyöräile translates just as well to "are not cycling" as it does to "do not cycle".