People who have been in Spain probably were lost in translation with the way spanish people order coffee. They have their special types that are quite useful to know if someone is a coffee lover.

So here is an unprofessional list that I made during my visit to Spain:

Cafe solo: a single espresso. So simple.

Cafe doble: a double espresso

Cafe americano: cafe solo with more water in it. 

Cafe cortado: an espresso with just a bit of steamed milk (usually 2:1 proportion). Very popular also in Portugal and in Latin America. In Cuba they call it cortadito.

Cafe con leche: an espresso with milk in a 1:1 proportion (half coffee half milk).
Cafe bonbon: a layer of sweetened condensed milk, a layer of espresso and foam milk on top. Very sweet for me but something difference, indeed. 

Carajillo: an espresso with alcohol usually brandy, rum or whiskey.

Cafe con hielo: my favourite type of coffee in summertime. If you ask for it they will bring you a hot espresso and a glass full of ice cubes. There is a ritual for this coffee: fist, you put the amount of sugar you want in the espresso and stir well for the sugar to dissolve. Then, you pour the espresso in the glass with the ice cubes. You wait just some seconds for the aroma to spread and the coffee to become cold and you enjoy!