Learn Swedish: Barnet tappar vanten i snön. - The child loses his mitten in the snow.

This is a great example of inalienable possession! In Swedish, when it is obvious from the context who owns a piece of clothing or a body part, you usually just use the definite article instead of a possessive pronoun. Since the child is the one dropping it, vanten naturally translates to "his mitten" (or "her/their mitten") in English.

Would it be wrong to say Barnet tappar sin vante?

It wouldn't be grammatically wrong, but it sounds slightly less natural in everyday Swedish. Swedes prefer vanten here because dropping your own clothing is a standard action where ownership is obvious. Using sin vante places unnecessary extra emphasis on the fact that it was the child's own mitten and not someone else's.

I thought the verb for "to lose" was förlorar. Why use tappar here?

Tappar literally means "drops," but it is the standard word used in Swedish when you accidentally lose a physical object (like a mitten, your keys, or your wallet). Förlorar is used for abstract things, like losing a sports game, losing hope, or losing a loved one.

Why is the definite form of snö written as snön instead of snöen?