Breakdown of Jag råkade trampa på hans fot.
jag
I
på
on / at / for (wait for) / in (believe in)
hans
his
foten
the foot
Questions & Answers about Jag råkade trampa på hans fot.
Why is there no att before trampa?
In this sentence, råkade acts as a semi-modal verb meaning accidentally or happened to. Just like traditional modal verbs such as kan or måste, it takes the bare infinitive of the next verb, so we use trampa directly without att.
Could we use sin fot here instead of hans fot?
No, because sin only refers back to a third-person subject of the same clause. Since the subject here is Jag (first person), using sin is grammatically impossible. We must use hans to show the foot belongs to a third party.
Is the preposition på strictly necessary after trampa?
Yes, to mean step on, you need på. If you just used trampa by itself, it would mean to tread generally or to pedal (like on a bicycle). Adding på specifically directs the action onto his foot.
How else could I say accidentally if I don't use råka?
You could use the adverbial phrase av misstag (by mistake). You would say Jag trampade på hans fot av misstag, which is perfectly correct, though using råkade is usually preferred as it sounds more natural and idiomatic in everyday spoken Swedish.