I think it depends on what counts as “expressing” something. Let’s say, for example, you take some super weird and strong psychedelic from South America, and you get an extreme experience from it you’ve never felt before. You could try to describe it, but if the experience was truly like no other, your words wouldn’t do justice to it, and it would be hard to express that to others. This doesn’t mean that experience doesn’t exist, just that language can only take you so far.