Questions & Answers about Olin eilen sairas, mutta tänään menen uimaan.
Why does the sentence use uimaan instead of the basic dictionary verb uida?
When you are going somewhere to do an action, Finnish uses the third infinitive illative form, which ends in -maan or -mään. Because you are going (using the verb mennä) specifically to swim, the basic verb uida changes to uimaan.
How exactly is the form uimaan built from the verb uida?
To make this form, you start with the verb's strong present stem and add the -maan or -mään ending based on vowel harmony. For uida, you drop the infinitive marker -da to get the stem ui-, and then just attach -maan to make uimaan.
Why isn't the word minä (I) used before the verbs here?
In standard and spoken Finnish, the first-person pronoun minä is very often dropped because the verb ending already holds that information. The -n at the very end of olin (I was) and menen (I go) makes it perfectly clear that 'I' am the subject.
The translation says 'I am going', so why doesn't menen have a special continuous ending?
Finnish does not have a separate continuous tense like the English '-ing' form. The standard present tense verb menen can mean 'I go', 'I am going', or even 'I will go'. Context words like tänään (today) help clarify exactly when and how the action is happening.