Most people think that learning a language is mainly about memorising words. In fact, the harder part is learning to hear where one word ends and the next one begins. When native speakers talk at normal speed, they do not leave clean gaps between words. They join them together, they drop sounds, and they reduce the small words almost to nothing. That is why a sentence you could read without any trouble can sound like noise when somebody says it out loud. The good news is that this is a skill, not a talent, and it improves faster than most learners expect.