Questions & Answers about Vilka höga ljud vi hörde igår!
Why do we use vilka here instead of vilken or vilket?
Vilka is the plural form. In exclamations meaning "What a...!" or "What...!", the word must match the gender and number of the noun. Since we are talking about "noises" (plural), we use vilka.
How can we tell ljud is plural here? It looks exactly the same as the singular form.
Ljud is an ett-word that ends in a consonant (ett ljud). These words don't change their spelling in the indefinite plural (one noise = ett ljud, multiple noises = flera ljud). We know it's plural in this sentence because it's paired with the plural word vilka and the plural adjective höga (which gets the plural -a ending).
Doesn't hög usually mean "high"? Why does it mean "loud" here?
That's right, hög usually translates to "high". But in Swedish, when you describe sound or volume (ljud), you use "high" instead of having a separate word for "loud". So ett högt ljud means "a loud noise".
Why doesn't the verb come second? Shouldn't it be "Vilka höga ljud hörde vi igår!"?