Learn Icelandic: Var þessi söngvari veikur í gær?

Þessi (this) changes depending on the gender of the noun it belongs to. Since söngvari (singer) is a masculine noun, we use the masculine form þessi. If the noun were neuter, we would use þetta instead.

Why does the adjective veikur end in -ur?

Adjectives in Icelandic must match the gender of the noun they describe. Because söngvari is a masculine noun, the adjective for sick takes the masculine ending -ur to become veikur.

Why does this question start with the verb Var?

Just like in English, Icelandic makes a yes/no question by putting the verb first. If it were a statement, it would be Þessi söngvari var veikur meaning This singer was sick. Moving var (was) to the front makes it a question.

Why is there an í before gær?

The phrase í gær is a fixed expression that means yesterday. Literally, it translates to in yesterday. Icelandic often uses prepositions like í (in) for time expressions, so it is best to memorize í gær as a single vocabulary chunk.