Se habla español
I just saw a commercial for a lawyer, and it said "se habla Español". Why do they say it that way -- what does it even mean? Why can't they just put, "We speak Spanish" or "Hablamos Español"?
It is the equivalent of the English "Spanish is spoken here", where you are not specifically mentioning who speaks it.
Se+ verb in the third person is a way of forming the passive voice that is quite commion so literally it means Spanish is spoken. There is a lesson on this on Spanishdict.
Even "Spanish spoken here" the passive "is" is often left out in English.
The passive is used when you don't know who is doing something or do not want to say who is doing it.
It is used a lot by politicians, diplomats and lawyers for obvious reasons.
So...se + baila. What would that mean?
The "se" in your examples basically conceals the agent, the one who perform the action, thus indicating that the action is performed, but who or what does it is not presented as relevant.
Aquí se come bien. = You can eat well here. (not specifically "you", but anyone)
Se ve mucho fútbol. = People watch a lot of soccer.
Se lee menos que antes = People read less than before.
Se compran libros usados = We buy second hand books.