What are the levels of proficiency in English and the vocabulary subsets at each level. As in how many words should a person know at each level of english proficiency and is there a reference list of this levels and vocabulary at each level. For example: beginner, intermediate, native, and on.
CERFL, the Common European Framework of Reference for Languages, is a guideline for progress in the learning of languages.
It specifies the level of mastery of language in 6 stages, A1, A2, B1, B2, C1, C2 from beginner to mastery.
It doesn't specify expected vocabulary numbers for each stage but others have found them experimentally for different languages. For English, Milton and Alexiou (2009) found roughly: A1 - 1500, A2 - 2500, B1 - 3250, B2 - 3750, C1 - 4500, C2 - 5000.