>This is almost exactly equivalent to saying that an average ten year old can read the New Yorker. It is not because it is fundamentally incorrect to say that

>This is almost exactly equivalent to saying that an average ten year old can read the New Yorker. It is not because it is fundamentally incorrect to say that the New Yorker is a C2 level text. The CEFR is not intended as a scale to measure the complexity of written text for native speakers and/or readers of a language, it is intended as a four part (listening, reading, speaking, writing) assessment scale of the overall language abilities of people. At most, one could say that a text was consistent with what would be expected of a successful CEFR C2 candidate in the reading portion of the test. One of the reasons that you cannot use the CEFR to characterise the proficiency of native speakers is that it assumes that you can understand texts of a similar complexity in your native language. Most such assessments are given to educated people, usually adults, so the texts reflect that. Yes, there are people who are not highly proficient by the standards of a native speaker at reading and particularly writing in their native language. Who knows, I may be wrong to think that they would easily pass the written portion of a CEFR test, certainly they would smash the oral portions. However the CEFR tests are fundamentally not designed to assess quality of education for native speakers. You could shoehorn them into that role but we already have other measures of language ability (in the US often calibrated to grade level) that are specifically designed to measure this.