Learn Finnish: Otan salmiakkia, sillä minun tekee mieli napostella jotakin. - I will take some salty licorice, because I feel like snacking on something.

This is the specific syntax of desire (mielitekorakenne). The person experiencing the craving must be in the genitive case (minun), while the verb remains locked in the third-person singular (tekee). Grammatically, the word mieli (mind) acts as the subject. Literally, it translates to something like "my mind makes".

What form is napostella, and why is it used after tekee mieli?

Napostella is in the 1st infinitive (the basic dictionary form). When your craving involves doing an action, the tekee mieli structure is directly followed by this infinitive. Because the grammatical subject of the clause is mieli, you do not conjugate the action verb to match the speaker.

Why is the pronoun jotakin (something) in the partitive case here?

The verb napostella (to snack or nibble) implies a continuous, unmeasured, or open-ended action, which requires a partitive object. Jotakin is the partitive form of jokin. If you craved a specific, whole item, you might use the accusative, but casually snacking on "something" is inherently unquantified.

The verb napostella ends in -ella. Does this suffix add a specific nuance?