From the Foreign Language Training website, we find e.g.:
The following language learning timelines reflect 70 years of experience in teaching languages to U.S. diplomats, and illustrate the time usually required for a student to reach “Professional Working Proficiency” in the language, ...
Foreign Language Training, Foreign Services Institute
What's confusing me is the notion of "class hours" above. E.g., I currently have 2 hours of class each week, and maybe 20-ish hours of self-study per week. Indeed, (for me at least) class hours are merely the tip of the iceberg when it comes to study.
Question: When the Foreign Services Institute says "X class hours" are required, how many hours of self-study are assumed?