Learn Finnish: He olisivat valinneet sinut ääntenlaskijaksi, jos olisit tullut ajoissa. - They would have elected you as the vote counter if you had come on time.

The verb valita (to choose/elect) requires the role or position someone is chosen for to be in the translative case (-ksi). The translative case expresses a change of state or taking on a new role, which translates smoothly to "as the vote counter" in English.

How exactly is the compound word ääntenlaskijaksi built?

The first part is äänten, which is the genitive plural of ääni (voice/vote), meaning "of the votes". The second part is laskija (counter, derived from the verb laskea). Finally, the translative ending -ksi is added to the end because of the verb valita.

Why is the object sinut in the accusative case instead of the partitive sinua?

The verb valita usually takes a total object because electing someone is a complete, indivisible action. Even though this sentence describes a hypothetical situation, the imagined result "would have been" fully completed, so we use the accusative personal pronoun sinut.

How do the verb forms olisivat valinneet and olisit tullut work together here?