[overeater]

I didn't downvote you but your tone is overly dramatic for some simple heuristics. Specifically you're just repeating two things over and over. Here's some simple answers:

1) you're right that ASCII was English only, but now utf-8 is the defacto standard, backwards compatible with ASCII, and good for every language. Use that, no BOM needed and the BOM is discouraged by the standard anyway.

2) dates can be YYYY-MM-DD as per the ISO standard. Also they're sortable as a string too as a nice side effect.

All good?