"Every sensible and rigorous theory of language shows that a perfect translation is an impossible dream." (Umberto Eco in _Experiences in Translation_, 2001)
To communicate exactly what another has said, I would need not only to use the same words, but also the same cadence, inflections, stances and facial expressions because all of these influence and are part of the message communicated. And, this is just what is necessary within a common language context; imagine 'translating' the message into another language that does not share the same idioms, metaphors, contexts, etc...!
Those who think that translation is simply knowing "equivalent" vocabulary do not understand the complexity of human language and human communication.
Because of this complexity, language learning in a classroom setting has obvious and great deficiencies. However...what is gained in the classroom are the very important building blocks for real language learning. On those building blocks of basic vocabulary and 'canned' conversations second language students must integrate 'real language' experience that comes through television news-casts from the country (countries?) that speak the target language (to provide contexts, connections, etc.), books--novels and texts--in the target language (to provide structure, vocabulary and cadence), movies and TV shows in the target language (to learn idioms, metaphors, common expressions), and popular music in the target language (to learn flow and cadence). In addition to all these, the best elements of language learning would be friendships with native speakers and experiences on the ground in a country that speaks the target language.
Even after years of classroom training, reading, writing and listening to the language, and time spent 'in country,' one will always find gaps, spaces and questions regarding the second language, but one will be ever closer to the real ability to translate, to move between languages with confidence and grace.
Now...try to translate this entry into your native language...and send me a copy!