What is a collocation and why is it important?

I was helping a non-native English speaker edit an essay and I came across several phrases that sounded foreign to me, for example, "changed our life to the best," and "illnesses that kill people daily." These sound more natural to my ear as, "changed our life for the better," and "fatal illnesses."

Later this week, I read an article in an asian EFL (English as a Foreign Language) journal about 'collocations'. This was a new word for me. Basically, researchers in linguistics gather together a bunch of data - ideally transcribed speech, but usually, written text, and analyze it. There are interesting patterns with regard to how often some words follow other words. When words tend to appear together, this is called 'collocation'. "For the better" is a common phrase for a native speaker, so it makes sense that a close but not exact substitution sounds foreign. The article actually finds a correlation between speaking proficiency of English by EFL learners in Taiwan and knowledge of collocations in English. That said, it is still unclear whether explicitly teaching collocations directly improves speaking and writing. Well, my view is that knowing some common collocations can't hurt. The article is titled, "Lexical collocations and their relation to speaking proficiency of college EFL learners in Taiwan." It's Article 9 or Volume 10 at this link: http://www.asian-efl-journal.com/March_08_jth.php

Here are a few examples of collocations:
carry something too far (He carried the joke too far.)
take care of something (I have to take care of a few things at the office.)
draw her attention to something (Bill drew her attention to the note on the door.)

And now for the word of the post: archive - "a repository or collection especially of information." It can also be a verb, "to archive," or file in such a repository. So if the journal article is not available in the current periodical section of the library, it's probably been archived.