Learn Swedish: Vilken linjal är smalast? - Which ruler is narrowest?

No, it is a false friend! The base adjective here is smal, which means "narrow" or "thin". To say "small" or "smallest", you would use liten and its superlative form minst. So smalast translates to "narrowest" or "thinnest".

How do we form the superlative "narrowest" in Swedish?

For regular adjectives like smal, you simply add -ast to the end of the base word to make the superlative (the "most" form). So smal (narrow) becomes smalare (narrower) and smalast (narrowest).

Why do we use vilken instead of vilket here?

Vilken means "which" and must agree with the gender of the noun that follows it. Because linjal (ruler) is an en-word (en linjal), we use the en-form vilken. If it were an ett-word like ett hus (a house), you would use vilket.

Why is linjal in the indefinite form?

In Swedish, the question words vilken, vilket, and vilka are always followed by a noun in its indefinite (basic) form. Even though you are asking someone to pick a specific item, you say vilken linjal (which ruler), never vilken linjalen.