Nine out of ten times, when a sentence just doesn’t make any flippin’ sense, even though you know all the words, it’s because of the evil workings of a preposition.
Compared to the masses of verbs, nouns and adjectives that exist in a language, the number of prepositions is miniscule. European languages have, on average, what, maybe thirty…? And yet, using those pesky little words correctly takes longer to learn than anything else. It’s also the first thing that goes when you lose regular contact with a language.
English phrasal verbs (which are, essentially, verbs married to prepositions) are infamous for making students despair. Take the verb “to look” as a random example: Look at, look for, look out for, look about, look over, look after… the preposition completely changes the meaning every time. English has thousands of phrasal verbs, including colloquial and regional variations that don’t appear in any dictionary.
To make matters worse, many have several, often completely different meanings depending on context. “To make out” is a prime example. Adding the preposition “on” to the phrasal verb “to go down”, gives it a completely new dimension… 😉
Other languages also have phrasal verbs, and plenty of them, Spanish being no exception. It took me ages to figure out, for example, that “dar con”, which literally translates as “to give with”, actually means “to find/encounter”. Makes no intuitive sense whatsoever!
When people are taught German as a foreign language, they are told that specific prepositions often correspond to specific cases, e.g. “mit” (with) always takes the dative. So, if you don’t know the correct preposition to start with, chances are you’ll get all the noun and adjective endings wrong as well, resulting in an irreparably screwed up sentence.
Even in fairly closely related languages like English and German, prepositions do not correspond. In German, you give “after”, not “in” and you depend “of” someone or something. Not all prepositions exist in every language, making translations cumbersome and learners tear their hair out.
It is generally drilled into students to learn prepositions in conjunction with a set of common verbs, e.g. “to concentrate on” and “to insist on” are a couple of classic examples, where only one preposition is viable, but in most cases, are just too many different possibilities for all of them to be learnt by rote.
In short, the only way to get your prepositions down to a pat is by knowing what sounds ‘right’ and what doesn’t. And this, as some of you will have found out, takes aeons of exposure. In fact, I’d say, that it’s impossible to achieve unless you’ve actually been living for years and years and years in a country where the language is spoken.