If you are a non-native teacher of English, the CELTA certificate will provide you with an international English teaching qualification that is recognized in most countries.
Continual assessment takes place during the CELTA course which is validated by an external assessor appointed by Cambridge University
You'll have to pass a test on:
The course lasts 4 weeks. Teaching practice and lesson observation takes place where you study.
So if you want to be recognized as an International English teacher in most parts of the world you'll have to get your CELTA certificate as soon as possible.