Questions & Answers about Minä leivon kakun tänään.
Why is it kakun instead of just kakku?
In this sentence, you are going to bake a whole cake. Because the action will be completely finished (a total action) and it is a positive sentence, the object kakku takes the -n ending to become kakun. This is called the genitive-accusative object.
The translation says "I will bake", but isn't leivon just the present tense?
Yes, leivon is the present tense. Finnish does not have a separate future tense, so the present tense is used for future actions too. Using the total object form kakun actually helps signal this: it shows you intend to follow through and finish making the cake.
Why is there only one 'k' in the middle of kakun when the basic word is kakku?
This is due to a rule called consonant gradation. When you add the -n ending, it closes the final syllable. This forces the strong double consonant kk in kakku to weaken into a single k in kakun.
Do I have to use the word minä here, or can I just say Leivon kakun tänään?
You can definitely drop minä! The -n ending on the verb leivon already clearly tells the listener that "I" am doing the action. In everyday Finnish, it is very common to leave the "I" or "you" pronouns out.