Ketä sinä odotat pysäkillä?

you

Breakdown of Ketä sinä odotat pysäkillä?

• odottaa: to wait for
• -llä: at
• pysäkki: the stop

Questions & Answers about Ketä sinä odotat pysäkillä?

Why is it ketä and not kuka?

Kuka is the nominative form of “who” and is used when “who” is the subject of the sentence:

• Kuka odottaa? – Who is waiting?

In Ketä sinä odotat pysäkillä?, “who” is not the subject; it is the object of the verb odottaa (“to wait for”).

The object form of kuka depends on case:

• nominative: kuka (subject)
• genitive: kenen
• accusative: kenet
• partitive: ketä

The verb odottaa always takes its object in the partitive case, so “who” must be in the partitive: ketä.

So the structure is literally:
Ketä (whom) sinä odotat (you are waiting for) pysäkillä (at the stop)?

Why does odottaa use the partitive (ketä) instead of something like kenet?

In Finnish, some verbs have a fixed “case requirement” for their objects. Odottaa is one of these verbs: it always takes its object in the partitive case, regardless of whether the waiting is finished or ongoing.

Examples:

• Odotan bussia. – I’m waiting for the bus. (bussia = partitive)
• Odotatko minua? – Are you waiting for me? (minua = partitive)
• Ketä odotat? – Who are you waiting for? (ketä = partitive)

Using kenet here (accusative) would sound ungrammatical to native speakers:
✗ Kenet sinä odotat pysäkillä? – wrong with odottaa.

So you simply memorize: odottaa + partitive object.