I'm spending time trying to wrap my head around 'wa' and every time I think I understand where it should go, I make a mistake. In this example from module 1.6, if "wa" signifies the subject of a sentence, then in the following example:
Are you Sayaka?
Sayaka san desu ka / さやか さん です か
Why wouldn't it be:
Sayaka san wa desu ka / さやか さん は です か
Or can you say it both ways, and the first example is less formal?
If the second example is incorrect, then how would this mistake sound if you tried to say it in English (that would help me grasp why it would be a mistake).