Un spanish dime sorda are usted diferentes, like "coger". In spanish (Spain) is "take" but in Argentina is "fuck"
Locales aren't meant to be international. They're meant to be specific.
Locale are Language-Region. For example, there's EN-US, EN-AU, EN-GB. They all share "English" but different regions have different localizations. Dates, currency, and measurements are different.
Spanish (Mexico) is generally compatible with most of South America.
Spanish (Spain) is the European variant. You'll have € instead of $, 24 hour time instead of a.m./p.m. and commas instead of periods for decimal points.
Spanish (International) isn't a real locale (though Latin American Spanish is known as ES-419).
Edit: I will add that there International Keyboards exist, but are different from Locales. This is generally understood as Base Language + International keys (for example AltGr).
There are variations to Spanish I think. The Spanish in Mexico may be slightly different from Spain, El Salvador, Guatemala, etc...
How Spanish (int) works, is it the Spanish from Spain? We don't have something like that for Portuguese, it's either Brazilian or Portugal.