When I was quite a bit younger, I didn't speak much of anything... I concentrated on the really important things in life like milk and diapers and chewing on my toes. But it didn't take me long to figure out that various noises could be really important, like warning me I was about to be picked up and have a bottle stuffed in my mouth.
Eventually I figured out that I could make similar noises, and it's been pretty busy since.

I was looking for my hardcover copy of The Fox Woman, a novel by Abraham Merritt that was later expanded (or possibly completed) by superlative artist Hannes Bok, to see if it included a particular story fragment or not, and happened upon a book given me a long, long time ago by Tsung Chin (晉聦), the head of the Chinese Language Program at the University of Maryland: 25 Centuries of Language Teaching, by LG Kelly.

The book is obviously geared toward language teaching and acquisition, but take a look at some of these quotes:

"We do not learn from word as mere word, that is as sound and noise. Those which are not signs cannot be words. If I hear a word I do not know whether it is a word or not until I know what it means. Once we establish its link with things, we come to know its meaning." – St. Augustine, AD 389

"Once things are known knowledge of words follows. Hearing words does not result in learning. We do not learn words we know; be we can not hope to learn words we do not know unless we have grasped their meaning. This is not achieved by listening to the words, but by getting to know the things signified." – St. Augustine, AD 389

"Even supposing one has a perfect grasp of the theory it is the production of the sounds that counts." – Lockhart and Jones, 1908

"All languages, both learned and mother tongue, be gotten, and gotten only, by imitation. For as ye use, so ye learne to speake; if ye hear not other, ye speak not yourself; and whome ye onlyi heare, of them ye only learne." – Ascham, 1570

There are lots more, not to mention the fascinating text of the book itself, but I think you get the point. All these people, whom the author obviously thought were imporrtant enough to quote in his own book, feel that study is insufficient to master a language. This is a point I cannot stress enough, and have touched on here again and again... even if you master the dictionary and the grammar books, you will still not really grok the language, because you'll miss all the cultural referents.

Like the word "grok," for example... many people reading this blog may have recognized it, but basically I think it is limited to people who read that particular Heinlein in English, or possibly a few Western European languages. I don't think it ever really gained popular usage in the computer industry, for example, as emphasized in that link. If you've read the book then you'll have a good understanding of what the word means; if you haven't, running into an unannounced "grok" on the page could cause quite a problem for the reader.

I am a firm believer in translating into your native language.
I was recently chided about that by a Chinese translator who moved to the States in middle school and has been there since... "since" being like forty years, I think. I admitted that I should have said "native-level" and not "native," but in any case entering a culture in your teens and living in it for a couple decades is probably an excellent way to go native. It's about what I did, now that I think of it.

There are just so many cultural referents that are buried in literature, so difficult to ferret out and equally difficult to express in fluid English. People I met in Japan would sometimes refer to me as "Mr. Ed," and wonder why I winced every time they said it. But if a character in a book winced for the same reason, how would a translator put that into Japanese without either adding a boring footnote or just sounding like he'd missed the point entirely? If you have a suggestion I'd love to hear it...

Some Japanese have asked me how I expect to be able to capture all the Japanese referents in a source text, even assuming I can translate what I understand perfectly. Excellent point, and I agree: I admit that there are probably places I missed what the author meant entirely. With practice and enough egg on my face, though, I have reached the point where I can usually tell when something looks funny. A sentence doesn't seem to jive, a word seems to be missing, a character doesn't respond naturally to what I perceive as the situation... and because some element of the scene doesn't ring true, I can ask a Japanese to check. Once the meaning is clear, the ability to express it accurately in readable English is crucial.

What is important to note here is that sometimes I am wrong and there was no meaning I missed. Sometimes there is an obvious (in retrospect) meaning I totally overlooked. And sometimes a number of Japanese will disagree on the possible meaning(s) of the piece entirely... pointing up, once again, that the interpretation of the reader (and the translator) is crucial and exceedingly difficult to pin down.

Let me close this with another great quote, this one courtesy of Steven Venti:

"A word is not a crystal – transparent and unchanging; it is the skin of a living thought, and may vary greatly in color and content according to the circumstances and time in which it is used." – Oliver Wendell Holmes, Jr.