Learn Finnish: Myyjä myy hyviä juureksia. - The vendor sells good root vegetables.

When forming the partitive plural, you add the plural -i- followed by the partitive ending (-a or -ä). For words ending in -a or -ä like hyvä, the final vowel drops out to make room for the plural -i-. So hyvä becomes hyv- + -i- + -ä = hyviä.

The basic word for root vegetable is juures. How does it become juureksia?

Words ending in -es (like juures) have a stem that ends in -kse-. The basic stem of this word is juurekse-. To make it partitive plural, the final -e drops before the plural -i-, and we add the partitive ending -a. So, juurekse- becomes juureks- + -i- + -a = juureksia.

Why are the root vegetables in the partitive plural here?

We use the partitive plural because the vendor is selling an undefined amount of root vegetables (basically "some good root vegetables"). Additionally, the verb myydä (to sell) typically takes a partitive object when the action is an ongoing process rather than a completed transaction of a specific, exact batch of items.

Myyjä (vendor) and myy (sells) look almost identical. Are they related?