There are both strong (irregular) and weak (regular) verbs in Norwegian, and these verbs form their past and present perfect tense forms in different ways.
Strong verbs have a vowel change in the the stem of the past and present perfect tenses. Since there are few patterns to these vowel changes, the past and present perfect tenses have to be memorized.
skrive | skrev | har skrevet | (write, wrote, has written) |
drikke | drakk | har drukket | (drink, drank, has drunk) |
Weak verbs have regular endings on the stem of the past and present perfect tenses. In English, there is just one set of regular endings added to indicate past and present perfect tense: ed. In Norwegian, there are four different sets of endings. However, these endings are added according to regular patterns, so one should learn the patterns rather than memorizing every verb.
vaske | vasket | har vasket | (wash, washed, has washed) |
like | likte | har likt | (like, liked, has liked) |
prøve | prøvde | har prøvd | (try, tried, has tried) |
bo | bodde | har bodd | (live, lived, has lived) |