You speak the language with a high degree of fluency meeting all professional needs. You have a diverse vocabulary and you very rarely commit errors.
You speak the language fluently enough to be able to participate in most conversations about social and professional topics. If needed, you can speak to clients as people don’t have trouble understanding you. You might commit some grammatical errors or have to search for words when talking about an unfamiliar topic.
You can participate in casual conversations about current events, work and family. You can understand most conversations regarding non-technical topics but still struggle with fluency and grammar.