???? that is called fluency

Not really. Fluency is probably closer to 70-95% comprehension, combined with an ability to assume the rest. I assume the comment is talking about native level comprehension, which is still only like 99.99%

Source: native English speaker in Europe. I have to explain/reword several words/expressions per day to people who would be by all means considered fluent.

(all numbers in this comment were estimated based on experience)

I wouldn't consider anyone "fluent" who has only 70% comprehension. More like 90%+. If you're assuming things based on context that is a marker of a low level of comprehension.

Im also a native English speaker and have to explain English words daily to other native English speakers. Dont really think that matters. Some words are more common than others.

I would say "full comprehension" would mean you don't need words and phrases explained to you on a daily basis.

And to each their own. Fluency is a bad metric because it means something different to everyone. If you live in a language, work in a language, and have friends in a language, most people would consider that fluent. I've met many, many people who qualify with a much lower comprehension level than 90%.

Also, speaking from experience, I'll often "comprehend a sentence 100% in another language". Then I'll really listen to it again and realize I'm not really sure about half of the words. I have a vague idea of most of them and in context my brain get's it and self-reports full comprehension.

I think "full comprehension" is a substantially higher bar than "fluency".

"Also, speaking from experience, I'll often "comprehend a sentence 100% in another language". Then I'll really listen to it again and realize I'm not really sure about half of the words. I have a vague idea of most of them and in context my brain get's it and self-reports full comprehension. I think "full comprehension" is a substantially higher bar than "fluency"."

I get it, and in my experience, when I find myself relistening and not being sure about "half the words," it means Im not fluent!

I wasn’t claiming fluency in these languages, just making a point that comprehension is normally very over-exaggerated, and that “full comprehension” is a long way off from just average “comprehension”, and in most cases not needed to converse/listen/read. A big part of fluency is being able to deal with a certain level of ambiguity

Have you ever learned a language? Because that's what it is for a very large percentage of people.

Nonsense, that's called 'learning a language' and is done by many who move abroad. I'm Dutch but more or less fluent in English and Swedish, can come quite far in German and make myself understood in and understand French. I'd have to learn local idioms in any of those countries, including the Netherlands since some expressions are really local and don't see much of any use outside of the village or county.