Questions & Answers about ¿Bailas mucho en la casa?
I don't see a word for 'Do' in this question. How do we know it's a question?
In English, we use helper words like 'Do' or 'Does' to ask a yes/no question. Spanish doesn't do this! To turn a statement like bailas (you dance) into a question, you just make your voice go up at the end when speaking, and add the upside-down question mark (¿) at the beginning when writing.
Where is the word for 'you' in this sentence?
In Spanish, the 'you' is already built into the verb ending of bailas. You can add the word tú for emphasis, but it is usually left out. If you do include it, you can put it before the verb (¿Tú bailas...?) or switch the order and put it after the verb (¿Bailas tú...?).
Why is it en la casa (in the house) instead of just saying 'at home'?
Both en casa (at home) and en la casa (in the house) are correct and frequently used in Latin America to mean 'at home'. Spanish often includes the word for 'the' (la) with places, even when English drops it.