Questions & Answers about Kiitän sinua avusta.
The dictionary form is kiittää, meaning to thank.
Kiitän is the 1st person singular present tense form, so it means I thank or I am thanking.
A quick pattern:
- minä kiitän = I thank
- sinä kiität = you thank
- hän kiittää = he/she/they thank
So in this sentence, kiitän tells you that the speaker is the one doing the thanking.
Because sinua is not the subject here; it is the person being thanked.
- sinä = you as the subject
- sinua = you in the partitive case
The verb kiittää normally takes the person thanked in the partitive:
- Kiitän sinua = I thank you
- Kiitämme häntä = We thank him/her/them
So sinua is used because Finnish grammar requires that form after kiittää.