The Common European Framework of Reference (usually abbreviated to the CEFR or CEF) helps describe what language learners can do a particular level. It is language neutral and is used by all languages to measure or mark proficiency.
The CEFR has 6 broad levels of ability, namely: A1, A2, B1, B2, C1 and C2, with A1 being basic and C2 being highly proficient or native-level or bilingual ability. Each levels is assessed on the 5 different skills of language: Spoken Interaction, Spoken Production, Listening, Reading, and Writing. Each of which has ‘can do’ statements which help to assess or mark proficiency of the learners.
The CEFR has over the years helped in providing a good framework in development of assessment tools and language learning and training materials in English and other languages.