Basic can be used to understand some basic words and phrases, but cannot hold a conversation.
Intermediate – This level indicates that you can hold a basic conversation but have a limited vocabulary, your grammatical understanding is yet to improve and you have satisfactory reading ability.
Proficient– you are proficient in a language if you are able to speak, read and write the language. At this level you will be able to hold a good conversation with a native speaker. However, you might find it difficult to keep pace with a native speaker and struggle to find appropriate words at times.
Fluent – as a fluent person you have complete understanding of the language and can even understand colloquialisms. You can speak and understand the language very comfortably however, you are not the native speaker of the language.
Native – this is used if a particular language is your mother tongue and you can read, write and speak very comfortably in the listed language.
ILR Interagency Language Roundtable, CEFR Common European Framework of Reference for Languages, ACTFL the American Council on the Teaching of Foreign Languages are some additional ways of mentioning your language skills on the resume.
Based on what level of understanding you have for a particular language, and the preferred rating method the employer you are applying for a job prefers, you can use these on your resume.
Now let us understand a few things about how actually you should project your language skills on the resume.