It’s incredible but a lot of people think that in Mexico we speak “mexican” (It’s almost the same mistake when some people say that in Brasil Speak brasilian) well, for everyone who never cares about “international history” maybe they have this big mistake.
Mexico was conquered by Spain (España) so, it’s why we speak Spanish, also, you can say that we speak Spanish from Mexico because it’s a huge different. They have different way to express something or someone.
It should be mentioned that a friend of mine has a dictionary where the title is “learn Mexican Language” but I think the best way of that title should be “Learn Spanish Idioms from Mexico”. But when I saw that book, I can see that maybe is because there is confusion in the past.
Then to liberate the great unknown, in Mexico speaks Spanish.
