The Common European Framework of Reference for Languages (CEFR) is elaborated by the Council of Europe to support language teaching and learning.

The CEFR establishes the six levels A1, A2, B1, B2, C1 i C2 in such a way that each level is defined through a set of specific skills within the following areas:

- reading comprehension
- listening comprehension
- speaking skills
- writing skills

This means that lexical and grammar knowledge as well as independent usage progress gradually from the first level (A1) to the highest (C2).

For most levels an official exam certifies the corresponding lingustic skills, and at present 38 languages forms part of the CEFR. This way it is easy to compare the various officials certificates of the different languages.

Likewise, whenever a specific level is required - for example to apply for a job or to access a university or another higher education institution -, it is easy to find out the contents and thereby easy to determine whether the existing level is sufficient or if further studies are necessary.

The six levels are summarized by means of the following can-do statements:

A1: Corresponds to: Trinity grades 1, 2 / Cambridge ESOL exam: Movers (YLE)
Can understand and use familiar everyday expressions and very basic phrases aimed at the satisfaction of needs of a concrete type. Can introduce him/herself and others and can ask and answer questions about personal details such as where he/she lives, people he/she knows and things he/she has. Can interact in a simple way provided the other person talks slowly and clearly and is prepared to help.  

A2: Corresponds to: Trinity grades 3, 4 / Cambridge ESOL exams: KET & Flyers YLE 
Can understand sentences and frequently used expressions related to areas of most immediate relevance (e.g. very basic personal and family information, shopping, local geography, employment). Can communicate in simple and routine tasks requiring a simple and direct exchange of information on familiar and routine matters. Can describe in simple terms aspects of his/her background, immediate environment and matters in areas of immediate need.  

B1: Corresponds to: Trinity grades: 5, 6 / Cambridge ESOL exam: PET
Can understand the main points of clear standard input on familiar matters regularly encountered in work, school, leisure, etc. Can deal with most situations likely to arise whilst travelling in an area where the language is spoken. Can produce simple connected text on topics, which are familiar, or of personal interest. Can describe experiences and events, dreams, hopes & ambitions and briefly give reasons and explanations for opinions and plans.  

B2: Corresponds to: Trinity grades: 7, 8, 9 / Cambridge ESOL exam: FCE
Can understand the main ideas of complex text on both concrete and abstract topics, including technical discussions in his/her field of specialisation. Can interact with a degree of fluency and spontaneity that makes regular interaction with native speakers quite possible without strain for either party. Can produce clear, detailed text on a wide range of subjects and explain a viewpoint on a topical issue giving the advantages and disadvantages of various options.  

C1: Corresponds to: Trinity grades: 10, 11 / Cambridge ESOL exam: CAE
Can understand a wide range of demanding, longer texts, and recognise implicit meaning. Can express him/herself fluently and spontaneously without much obvious searching for expressions. Can use language flexibly and effectively for social, academic and professional purposes. Can produce clear, well-structured, detailed text on complex subjects, showing controlled use of organisational patterns, connectors and cohesive devices. 

C2: Corresponds to: Trinity grade: 12 / Cambridge ESOL exam: CPE
Can understand with ease virtually everything heard or read. Can summarise information from different spoken and written sources, reconstructing arguments and accounts in a coherent presentation. Can express him/herself spontaneously, very fluently and precisely, differentiating finer shades of meaning even in more complex situations.  

http://www.coe.int/t/dg4/education/elp/elp-reg/Source/Key_reference/Overview_CEFRscales_EN.pdf