The Interagency Language Roundtable scale is a set of descriptions of abilities to communicate in a language. It is the standard grading scale for language proficiency in the United States's Federal-level service. It was originally developed by the Interagency Language Roundtable (ILR), which included representation by United States Foreign Service Institute, the predecessor of the National Foreign Affairs Training Center (NFATC).
The scale grades people's language proficiency on a scale of 0–5. The designation 0+, 1+, 2+, 3+, or 4+ is assigned when proficiency substantially exceeds one skill level but does not fully meet the criteria for the next level. Thus the scale totals 11 possible grades.
Grades may be assigned separately for different skills such as reading, speaking, listening, writing, translation, audio translation, interpretation, and intercultural communication. For some of these skills, the level may be referred to with an abbreviation, for example, S-1 for Speaking L