I think your area of speciality makes it harder;

I work in Sports/MSK and have worked in around 7 or so countries now (mostly non-English speaking). I am Australian, worked in Africa and Asia. Some countries (but not many) do require a exam, actually most don't. Usually a review of your experiences, references, education transcripts and home country registration are probably is required. But the issue being this will take a long time and a lot of money, for example for me to get registered in England took over 6 months to get approved, and around $800 pounds. That said, Australia, Canada, and USA require exams, and most the rest do not unless they think your experience and transcripts are not up to their standards. Now the issue is medical systems are vastly different worldwide, i have it easier because MSK/Sports Physio is different to hospital. This is because in many countries the exams (or medical board registration) is only required for those who work in the hospitals. But the world has 204 countries, and even if they not native English speakers, most countries in the world have highly education part of society with great English. And i can say i have been able to communicate very well even in mainland China, Japan, and Korea.