Questions & Answers about Han hörde ljudet komma uppifrån.
How exactly does uppifrån mean 'from above'?
Can I just say från uppe instead of uppifrån?
No, that would sound unnatural in Swedish. You generally cannot use the standalone preposition från immediately before location adverbs like uppe (up/above) or nere (down/below). You must fuse them into one word using the -ifrån suffix.
Why is there no att before komma?
Just like in English, verbs of perception (like hearing, seeing, or feeling) take a bare infinitive without att (to). Because han hörde means 'he heard', the following verb simply becomes komma (come) instead of att komma (to come).
Why does the sentence use ljudet rather than ljuden?