Learn Romanian: Unde este soția ta?

In Romanian, when you use a possessive adjective like ta (your), the noun before it must have the definite article attached to it. You are literally saying "the wife your." Since soție means "wife," you have to use soția ("the wife") before adding ta.

Why do we use ta for "your" here?

Possessive words have to match the gender and number of the thing being owned. Because soția (the wife) is a feminine, singular noun, you must use the feminine, singular form for "your," which is ta. If you were asking about a masculine noun, like a husband, you would use tău instead.

How did soție (wife) turn into soția (the wife)?

For feminine nouns that end in -ie (like soție), you form the definite word for "the" by replacing the final -e with an -a. That gives you soția.

Can I put ta before the noun, like we do in English?

Not in everyday Romanian. Possessive words like ta almost always go immediately after the noun they describe.