Here is an article about the concept that kids learn languages in chunks and that second language acquisition can be done in the same way. I feel that learning phrases is an important part of language learning, but I still come down to individual words as the key basic element of language learning. Words, words and more words. If we learn these, through massive reading and listening and few other learning tricks, the rest kind of falls into place. I still believe that the number of words you know ( passively) is a reasonable measure of your ability in a language.