The rest of the Spanish-speaking world is unaware, too. I am foreigner who learned Spanish of Spain, and when traveling in Latin America the locals have often made fun of me for using the vosotros form of verbs. "There are umpteen Spanish-speaking countries, and only one says vosotros," they'd say.

"Not true!" I would try to defend myself. "They use vosotros in Western Sahara and Equatorial Guinea, too!" (On my first visit to WS in the early millennium I met many older Saharawis who spoke excellent Spanish as if they had grown up in mainland Spain, though now that demographic must be elderly or already passed away.)