[bayesian_horse]

Understanding spoken language means building a representation of the current sentence in your mind. For all but the shortest sentences, this can't be done word-by-word or even phoneme-by-phoneme. Humans have a working memory of 7+-2 items, and it gets quickly overloaded that way.

When we know a language well enough, we actually compress the sentence to a mental model that takes a lot less space in that working memory. But this only works when we know every word of the sentence and understand the grammar involved. Even one unresolved word often means the sentence expands from one chunk to at least three chunks.

Of course, your speaking skill also improves all the time. But at least in my case I feel like I can usually speak better than listen, in a new language (and I've had a few).