Learn Italian: Quello che mangio sa di terra, è disgustoso! - What I am eating tastes like dirt, it's disgusting!

When followed by the preposition di, the verb sapere takes on a sensory meaning: "to taste of" or "to smell of". Therefore, sa di terra literally translates to "it tastes of dirt".

Why does the sentence start with Quello che instead of Cosa to mean "What"?

In Italian, cosa is an interrogative word used primarily for asking questions. When "what" is used in a statement to mean "the thing that" or "that which", you must use a relative pronoun construction like quello che or ciò che.

Since this lesson is about sensory verbs, could sa di terra also mean it smells like dirt?

Yes! The expression sapere di can refer to both taste and smell. Context usually makes it clear which sense is being used. Here, the presence of the verb mangio (I am eating) tells us it means "tastes like".

Could I translate "tastes like dirt" literally by saying sa come terra?

No, that would sound very unnatural in Italian. While come does mean "like", the grammatically correct structure for having the flavor or scent of a specific thing is always sapere + di + noun.