Learn Italian: La nonna prepara l'arrosto la domenica. - Grandma makes the roast on Sundays.

In Italian, subjects almost always require a definite article like la (the). While we just say "Grandma" in English, Italian requires la nonna. You only drop the article if you are talking directly to her, or if you are using a possessive adjective with a singular family member (like mia nonna).

Doesn't prepara mean "prepares"? Why not use fa to mean "makes"?

You can use the verb fare (to make or do) in many contexts, but when talking about cooking or putting a meal together, Italians commonly use preparare. Translating it as "makes" simply sounds more natural in everyday English.

How does la domenica mean "on Sundays" rather than just "Sunday"?

When you put a definite article before a day of the week in Italian, it indicates that the action happens regularly on that day. So la domenica means "every Sunday" or "on Sundays". If you wanted to say she is making the roast this Sunday, you would leave out the article and just say domenica.