There are many different teaching certifications out there for aspiring English teachers. The most common ones are TEFL, TESOL, TESL, and CELTA.
While many countries will accept a TEFL, TESOL, or CELTA certification, it is important to note that some countries (and schools) may only accept a specific certification. It is common for schools in China and in some European countries to only accept teachers with a CELTA degree. Make sure you research the schools in the country you would like to teach in before getting you certification so you have the proper one.
A simple breakdown of these 4 common certifications is as follows:
TEFL – Teaching English as Foreign Language; allows you to teach English in countries where English is not the primary language.
TESOL – Teaching English to Speakers of Other Languages; lets you teach English to people whose native language is not English.
TESL –Teaching English as a Second Language; allows you to teach English to people who live in a country where English is one of the primary language.
CELTA – Certificate in Teaching English to Speakers of Other Languages; this is the official certificate of the University of Cambridge and is very widely recognized and respected. Some companies may only hire applicants with CELTA certifications in European countries and in China.
TEFL and TESOL certifications are essentially the same and allow you to teach English as a foreign language. A TESL certification is most useful if you are planning on teaching English in a country where English is the primary language, like America. CELTA is the preferred certification for people teaching in Europe, although a TEFL or TESOL certification is often an acceptable substitute.