Learn Swedish: Jag vaknade till på grund av oljudet. - I woke up briefly because of the noise.

While vaknade just means you woke up, adding the particle till implies a sudden, brief, or involuntary reaction. In this sentence, vaknade till means you just stirred or woke up momentarily because of the noise, but likely went back to sleep right after.

Could I move the particle till to the end of the sentence?

No, aspectual particles like till must stay firmly attached directly after the verb. Unlike some English phrasal verbs where the particle can move around, Swedish keeps them strictly together: vaknade till.

Could I use därför att instead of på grund av to say "because of"?

Not with this exact sentence structure. på grund av is a preposition used before a noun phrase like oljudet. If you wanted to use därför att, you would need to follow it with a complete clause containing a subject and a verb, such as därför att det lät så mycket.

What is the difference between oljudet and ljudet?

ljud simply means "sound" and can be pleasant or neutral. The prefix o- usually means "un-" or indicates a negative version of a word. So, oljud specifically means a bad, loud, or annoying noise.