A few people have chosen to use their signature to display the languages they speak or they are learning.
Some people may be using the CEFR indicators (A2, B1, etc) next to these flags. While these are (usually) only self-assessments, (people may have gone through the effort/expense of accreditation, but no one is asking for credentials on an internet forum), and the system is not without criticism, it is my view that these still provide a far more accurate indication of proficiency than the obsolete Duolingo 'levels' that used to be displayed next to flags. But, if you don't know what A1 means, this may well be meaningless to you as well.
I have summarized the CEFR levels below; my source is this article by Shannon Kennedy on the website Fluent in Three Months.
The Common European Framework of Reference for Languages, often referred to as CEFR or CEFRL, is an international standard for working out your ability within a language.
The A levels: Basic User
A1 | Beginner
At the A1 CEFR level, a language learner can:
Understand and use very basic expressions to satisfy concrete needs.
Introduce themselves and ask others questions about personal details.
Interact simply as long as the other person speaks slowly and clearly.
A2 | Elementary
At the A2 CEFR level, a language learner can:
Understand frequently used expressions in most intermediate areas such as shopping, family, employment, etc.
Complete tasks that are routine and involve a direct exchange of information.
Describe matters of immediate need in simple terms.
The “B” Levels: Independent User
B1 | Intermediate
At the B1 CEFR level, a language learner can:
Understand points regarding family, work, school or leisure-related topics.
Deal with most travel situations in areas where the language is spoken.
Create simple texts on topics of personal interest.
Describe experiences, events, dreams, and ambitions, as well as opinions or plans in brief.
B2 | Upper Intermediate
At the B2 CEFR level, a language learner can:
Understand the main ideas of a complex text such as a technical piece related to their field.
Spontaneously interact without too much strain for either the learner or the native speaker.
Produce a detailed text on a wide range of subjects.
The “C” Levels: Proficient User
C1 | Advanced
At the C1 CEFR level, a language learner can:
Understand a wide range of longer and more demanding texts or conversations.
Express ideas without too much searching.
Effectively use the language for social, academic or professional situations.
Create well-structured and detailed texts on complex topics.
C2 | Proficiency
At the C2 CEFR level, a language learner can:
Understand almost everything read or heard with ease.
Summarize information from a variety of sources into a coherent presentation.
Express themselves using precise meaning in complex scenarios.
Fluency in a language is highly subjective, and largely depends on what your goals are. If you are hoping, for example, to attend university in a certain language, or work professionally in a country where your target language is spoken, then working hard to achieve a C level will be important.
But maybe your goals aren't quite as formalised? You'd like to enjoy the literature, or pass the 'pub test' (can you spend a few hours at the pub communicating with others exclusively in your target language, and enjoy yourself doing so)? In other words, your primary aim is to use the language for fun, candid, informal - but meaningful communication with native speakers. Maybe you're just interested in understanding movies, films, or (in my husband's case) manga of your target language? Maybe you're planning on spending a few weeks visiting a country, and are hoping to interact with locals on your trip? Maybe you're just learning the language 'for fun' and have many more languages on your wishlist to tackle when you're 'done' with your current one. If you're in any of these categories, the B levels may well be all you need.
Regardless of your goals, I leave you with this quote:
We should learn languages because language is the only thing worth knowing even poorly. If someone knows how to play the violin only a little, he will find that the painful minutes he causes are not in proportion to the possible joy he gains from his playing. The amateur chemist spares himself ridicule only as long as he doesn’t aspire for professional laurels. The man somewhat skilled in medicine will not go far, and if he tries to trade on his knowledge without certification, he will be locked up as a quack doctor.
Solely in the world of languages is the amateur of value. Well-intentioned sentences full of mistakes can still build bridges between people. Asking in broken Italian which train we are supposed to board at the Venice railway station is far from useless. Indeed, it is better to do that than to remain uncertain and silent and end up back in Budapest rather than in Milan.
- Kató Lomb
Native
- Upper Intermediate | 
Beginner | 
Beginner (inactive)
N 
C2 (Speaking - C1) 
B1 (DL) 
/ fluent 
/ learning 
/ fan of 
(bs/bl)
(B1) 
(A)
(Busuu: B1) -