To add on to what you said - understanding is a subset of fluency. You also need to be able to adequately explain/communicate your thinking in order to be consi

To add on to what you said - understanding is a subset of fluency. You also need to be able to adequately explain/communicate your thinking in order to be considered fluent. This requires a sound "theory of mind for language" in order to be able to figure out when someone is misunderstanding you, and avoiding potentially confusing diction choices, which a lot of non-fluent speakers struggle with.