Learn Finnish: Suosittelen näitä hoitoaineita. - I recommend these conditioners.

Näitä is the partitive plural form of tämä (this). We use the partitive case here because the verb suositella (to recommend) always requires its object to be in the partitive. Because we are talking about multiple conditioners, both the pronoun and the noun must be in the partitive plural.

Why does the verb suositella require the partitive case?

In Finnish, verbs that express feelings, thoughts, or ongoing actions without a clear end point often take a partitive object. Suositella belongs to this group, just like rakastaa (to love) or odottaa (to wait for). You aren't doing something that physically completes or consumes the conditioners, you are just expressing a recommendation toward them.

The dictionary form of the verb is suositella. Why does suosittelen have a double "tt"?

This is because of consonant gradation. Suositella is a Type 3 verb. For these verbs, the dictionary form is in the weak grade with a single t. When we conjugate it by adding personal endings like -n for "I", the stem changes to the strong grade, doubling the consonant to tt.

How do we get hoitoaineita from its base form?