I agree with you that bilingual reference books are often not terribly helpful when learning a foreign language. I also think that you're spot on when you writ

I agree with you that bilingual reference books are often not terribly helpful when learning a foreign language. I also think that you're spot on when you write that reading extensively is an excellent way to improve your knowledge of a language. But in my experience, you can only do this once you have reached a certain stage in learning the language. Before that stage, it's critical to build up a sufficient vocabulary and (secondarily) to learn the grammar. I've learned several languages as an adult, and I made the most progress in the beginning by committing to learn at least 10 new words or phrases a day. Once you reach around 500 words (that's a wild guess, but it's in the ballpark), you should be able to start reading certain carefully-selected books and learning new words through context. In my personal experience, it's only at this stage of language learning that "immersion" is really effective. So yes, learning a language is far more than learning words. In fact, to underline what you wrote above, most trained translators explicitly attempt to map ideas, not words (although there are in fact multiple "translation paradigms" on how exactly to go about this). So absolutely, many words and phrases are specific to a given language, and don't map one-to-one. Nonetheless, as an adult learner, basic vocabulary -- combined with grammar -- provide you with a foundation upon which to build your language learning. Nouns like "man, woman, head, shoes, etc" and verbs like "go, speak, find, search". Without a basic vocabulary, it's pointless to try to build up oral fluency, or to read books. No serious language learner that I know willingly picks up a book in a foreign language and starts to study it without some preparation, or dives into in-depth spoken interactions with a speaker of the target language with no background in that language. Most try to establish the most common words of a language, memorize them, find a good grammar, study it, and only then do they start to interact with the spoken and/or written language. (Background: native English speaker who learned one foreign language as an adolescent and several others as an adult / ATA-certified translator with a decade of experience doing technical/medical translations. Currently: transitioning back to professional web development!)