The Council of Europe divided learners into 6 main bands (A1, A2; B1, B2; C1, C2) as part of the Common European Framework of Reference (CEFR) for Languages:

A Basic User
A1 Breakthrough
A2 Waystage
B Independent User
B1 Threshold
B2 Vantage
C Proficient User
C1 Effective Operational Proficiency
C2 Mastery

Note: the CEFR applies to people learning…