Actually, the situation is even weirder in Swedish! Even though we write "att", it is pronounced "o" when used to mark an infinitive but not when used like the word "that" in English. So, in the sentence

  Jag tror *att* han gillar *att* äta
  I think *that* he likes *to* eat

the first "att" (that) is pronounced similar to its orthography but the second one (to) is pronounced "o".

https://en.m.wiktionary.org/wiki/att#Swedish