Breakdown of Te tiedätte, koska te opitte nopeasti.
te
you (plural/formal)
koska
because
tietää
to know
oppia
to learn
Questions & Answers about Te tiedätte, koska te opitte nopeasti.
Why is there a "d" in tiedätte when the dictionary form is tietää?
Tietää (to know) is a Type 1 verb. To conjugate it, you use the stem tietä-. However, when you add the -tte ending for "you (plural)", it closes the syllable (tie-dät-te). This triggers consonant gradation, weakening the strong "t" into a "d".
Why does opitte only have one "p" when the dictionary verb is oppia?
This is another example of consonant gradation. Just like with the first verb, adding the -tte ending closes the syllable (o-pit-te). This forces the strong double "pp" from the stem of oppia to weaken into a single "p".
Can I drop the word te (you) in this sentence?
Yes! In Finnish, the verb endings already tell us who the subject is. Because the -tte ending specifically means "you (plural)", you can safely drop the pronoun and just say Tiedätte, koska opitte nopeasti.
How is the word nopeasti formed?
It comes from the adjective nopea, which means "quick" or "fast". By adding the -sti ending, you turn it into an adverb that describes how an action is done, very similar to adding "-ly" in English (quick becomes quickly).