There also exists another level to this problem. An example seems necessary. I will select a most mundane and seemingly harmless word. Take the Russian word for 'SPOON': 'Ложка' pronounced 'loshka'. If we examine the associations, we run into a few difficulties. A spoon is something that you eat with, generally made of metal, has a handle with a shallow, elongated bowl on the end. All these thoughts are also associated with 'Ложка', but their exist many others. A Russian, on hearing the word 'Ложка' is immediately confronted with the above concepts, but also with the strongly ingrained concept of punishment. It was customary to rap on the forehead an unsuspecting, misbehaving youngster at the table with spoon. Americans do not hold this association. But present in our (the American) culture is the phenomenon of the bending spoon. We have all seen (or at least heard of) a magician who can bend spoons with his or mind (The Matrix helps here). Another good example would be the idea of 'spooning', which refers to an intimate position for two people, originating with how spoons fit together nicely when stacked.
For every word, there also exists an implicit meaning and an explicit meaning. Explicit meanings evolve with the language (examples include 'coolie' and 'leatherneck'.), while implicit meanings are constantly being changed by the media.
So, in conclusion, we can see that, although a dictionary will tell us that 'spoon' and 'Ложка' are equivalent, cultural associations prove this false.
Thanks go to ideath for the 'spooning' reference, as well as the implicit/explict and poetry translation discussions. For more information, see linguistics, translation, machine translation, and russian.