Why Spain is harder for US passport holders
Spain is in the EU, and EU citizens can work there without a visa. As a non-EU passport holder, you generally need either a government-run programme visa, a student visa, or a rarer employer-sponsored work visa, since sponsoring a work visa is expensive and slow for most small language academies.
This is different from Korea or the Gulf, where passport lists (not EU membership) are the deciding factor. Here, the constraint is fundamentally about EU vs non-EU status.
