I would think that after making those sorts of announcements frequently for one’s job, one would learn just a few minor adjustments to improve accuracy.
The basic ones I can think of that would increase accuracy measurably are:
1. How to pronounce “Nguyen”
2. Spanish ‘j’ is close to English ‘h’
3. Spanish ‘h’ is silent
4. Spanish 'll' is close to English 'y'
5. Chinese ‘q’ is close to English ‘ch’
6. Chinese ‘c’ is like English ‘ts’
7. Chinese ‘x’ is close to English ‘sh’
8. Most languages do not use ‘a’ as in the American English “and”. If you have to guess, better is ‘a’ as in “father”. In general if you have to guess, the vowels of Spanish are usually going to be closer than the vowels of English for most languages.
If the airport announcers were taught these basics on day 1 it would make a tangible difference in people’s lives for so little invested effort.