Thanks, lrkr!
Yes, some knew nothing whatsoever vis-a-vis the foreign language and simply jumped in and picked it up by ear. I give them credit for their fearless endeavor, which was rewarded particularly out in service: foreigners in America were honored to be visited by young men who made a genuine effort to communicate in a tongue not their own.
We who received formal training over a period of many years were chosen to be speakers. You cannot get around the need to read and write your adopted language.
Gratefully,
CoCo