Learn Finnish: Leivon tänään tuoretta leipää.

In Finnish, adjectives must match the noun they describe in both number and case. Because the noun bread (leipää) is in the partitive case, the adjective describing it (tuore) must also be in the partitive case, becoming tuoretta.

Why are "fresh" and "bread" in the partitive case here?

We use the partitive case for the object of a sentence when it represents an uncountable mass or an indefinite amount. Here, you are baking an unspecified amount of fresh bread, rather than one specific, bounded loaf, so both tuore and leipä take the partitive ending.

The dictionary word for fresh is tuore. How does it become tuoretta?

Finnish words that end in -e follow a special rule. To form the partitive case for these words, you add -tta or -ttä instead of just -a or -ä. Because of this, tuore becomes tuoretta.

Why is the verb leivon when the dictionary form to bake is leipoa?

This happens because of a rule called consonant gradation. When adding personal endings like the -n for "I", the syllable becomes "closed," causing the strong consonant p in leipoa to soften into a v. This gives us leivon.