Mexican television does have some channels that are completely in Spanish. They are translated in Spanish. Channels such as A&E, TNT, etc., you are going to see them but they are in Spanish. If you want to have the English access then there are providers that are not Mexican such as Dish where you can have both English and Spanish channels.
People also tend to bring down their DirectTV subscriptions here in Mexico because they want to have English channels. I do not have DirectTV but I believe you have to have someone go around the system to install Dish or DirectTV for you here in Mexico but yes, it is possible. You can call Dish and tell them that you are in Mexico and request for them to set your access up for you.
(Dish network in Mexico logo, pictured.)