Questions & Answers about Mitäköhän mä teen tällä kaikella romulla?
How does the clitic -köhän work when attached to mitä here?
The fused clitic -köhän translates roughly to "I wonder". When you attach it to the question word mitä (what), it softens a direct question ("What will I do?") into a pondering, internal thought ("I wonder what I will do?").
Why does the clitic use the form -köhän instead of -kohan?
It follows the rules of vowel harmony based on the word it attaches to. Because mitä has the front vowels i and ä, the clitic must also use front vowels, making it -köhän.
Why do tämä, kaikki, and romu all take the adessive ending -llä or -lla in this sentence?
The adessive case is used here to mean "with" an object. In Finnish, modifier words like "this" and "all" must match the case of the noun they describe. So tämä, kaikki, and romu all get the adessive ending, becoming tällä kaikella romulla.
The translation says "will do", so why is the verb teen in the present tense?
Finnish does not have a dedicated future tense. The present tense is used for both things happening right now and things that will happen in the future. The context of pondering what to do makes it clear this is about a future action.