Prefixes in Swedish
Swedish has a lot of words with prefixes like för, be and so on. Is there any logic to how these prefixes change the meaning of the word they modify? Many times I have had to just look up the meaning from dictionary.
Sometimes yes, sometimes no. A lot of words that have used prefixes for a long time have lost their unprefixed meaning, and sometimes the sense of a word has changed but the prefix remains from its original meaning. Many words have been imported from other languages with their prefixes intact, and they often make sense unprefixed as well, but occasionally they don't.
I'll list some common prefixes and try to make sense of them.
- o-, e.g. omogen ("immature"), negates the meaning like English im- or un-. For trivia: it's common in northern Sweden to be able to prefix practically anything with o-, leading to words such as oi ("outside").
- an-, e.g. anlägga ("construct", "lay down"), original meaning "against", used to infer some kind of connection. It could be physical, like in angrepp ("assault"), or not, like in anmoda ("implore").
- för-, has multiple uses. A common one is to cause or intensify, e.g. förvirra ("confuse") - the same function that e.g. the en- in "enhance" has. It can also be used prepository, as in förbehålla ("stipulate") or förvarna ("give advance notice" or indeed "forewarn").
- be-, works like in German if you happen to speak German. And there's been a serious debate about whether to stop using the be- prefix entirely, as lots of words in Swedish don't actually benefit from them. But when you do need the prefix, it's typically to either make a connection (beundra - "admire", befalla - "order"), or to create an action verb (begrava - "bury").
- av-, e.g. avleda ("avert"), used like its preposition counterpart to mean "from", "down", or most typically "off". In the avleda example, leda means "direct" and av- means "off".
To add to your comment, most of those also exist in English with similar meanings and sounds, but with slightly different spellings, though they may be "non productive" in that new words are no longer formed using them.
- a-, e.g. arise, awaken, abide, amaze, etc. In English, has more the meaning of away/up/on/out.
- for-/fore-, like forewarn, but also forearm, forehead, forbear, forgive, etc. It works like in Swedish. In addition to enhancing the word, it can also carry the meaning of complete or to the greatest extent.
- be-, e.g. beleaguer, behold, behead, bemoan, bedazzle, befriend, etc. Similar to Swedish usage. Has a similar concept to Swedish på as in by/around/about/on/off, but also as an intensifier or to bring something into being.
- off-, e.g. offsite, offtrack, offtopic
I've got nothing for o- though :)
There's a book Verb med variation that helps understand the prefixes (or helps confuse you further, since it's in Swedish) and different meanings of some common verbs.