"Por" or "Para" - That is the Question
Let's Tackle Por & Para
The first problem with this pair of Spanish prepositions is that teachers and books often start out by saying that they both translate as for in English. This is only true... ok, most of the time. But what a way to guarantee confusion. I know you've heard that, so no harm in pointing out that it is a bad place to start. So let's start over. You've never heard of them, agreed?
The proper place to start is by showing that for does not mean one thing in English! I like to write the following sentence on the board and ask students what it means: I made the cake for mom. If the first question seems like a dangerous set up (why are they so scared to jump in with ideas?), I ask them: How many sentences are on the board? (as if that relieves any anxiety). I tell them there are at least six -- and tell them to read the sentence six times, each time stressing the next word. The last two readings are the ones that count. I ask them if for, in each case, conveys the same message (note that I do not ask if it means the same thing, because if they see the same letters, they assume it is one word, with one meaning -- such is the power of the curse of monolingualism!
Next, I point out that in the case when for is stressed, it means in mom's place (she may have been sick or busy, so I had to do the baking). When mom is stressed, it's possibly because it is mom's birthday -- she is the intended recipient. These two distinctions begin to crack the problem open and get students to admit to themselves that there can be one word with more than one meaning.
After I have presented this concept and obtained their intellectual consent, I point out that there are two prepositions in Spanish that distinguish these two meanings -- plus others, but that this example is a good place to start. I tell them that por is the preposition that would be used in Spanish in the first case and para in the second.
Next, I take a risk -- hoping that I have a class with powers of abstraction. I draw two circles on the board. Through one, I draw an arrow, all the way, through its diameter. I also draw an arc around part of its circumference and one within. I also draw a curving path around inside the circle. I draw an arrow pointing at the other circle.
I label the first circle por and the second para. As I do so, I tell them that por is static, and para is dynamic. I then tell them that para shows destination or deadline -- thus it refers to time or space. I write El avión va para Chicago and La tarea es para el lunes.
After these examples, I begin writing the usual chart showing the uses of por: through, along, by, in (spacial) and during (temporal) -- as I trace the lines I drew to symbolize these meanings on the circle labeled por. Then I add a few phrases beneath that circle to show means (por teléfono, por tren), exchange (cuatro monedas de a 25 centavos por un dólar), and a few stock phrases, such as por el bien de, por el amor de Dios, por favor, ¿por qué?, etc.
Under the circle representing the dynamic qualities of para, I write recipient (mom), direction toward (Chicago), in order to (I show para + infinitive in a sentence), unexpected comparison (¡Qué grande para un niño de siete años!), and intended purpose (Es una copa para vino).
Following this presentation, I do some oral work in English, asking which preposition would be used in Spanish.