TESOL (or TESL) stands for Teacher of English to Speakers of Other Languages. TEFL stands for Teacher of English as a Foreign Language, and CELTA is a British equivalent. In countries where English is not the mother tongue or official language, English is taught as a foreign language. The history of the global spread of English (See also Linguistic Imperialism, English as a Lingua Franca) has led to the current situation where English is taught not only in schools but in language centers and online. Unsurprisingly, the field has grown in the last twenty years with educational reforms pushing for English. Most higher education requires Academic English, and is often the language of academia, so many TEFL teachers are now teaching at tertiary institutions. In language schools it is a veritable industry from teacher education to textbooks.
Teaching requirements vary by type of educational institution: from online courses, some requiring very few hours, to master’s degrees, with many in between; most requiring the teacher to be a native speaker. Educational institutions include private schools, public schools, language schools, tertiary institutions, and business schools. The many certification options also have a range of time commitment and price that usually are matched to the type of educational institution and popularity and economic situation of the country, although certification requirements are rising as standardization and accreditation on global scales enforces higher standards of certification. Some countries and institutions pay very well but require more, while others accept less and pay less. A large number of expatriate people become teachers and go abroad, as an adventure or as a serious profession. Many are lacking cultural sensitivity and with only basic teaching methods and experience, while others adapt and stay abroad many years.
The entire scenario is embedded with the same conceptual and cultural debates this website is exploring- language-in-education policies that carry with them hegemonic and linguistically dominant ideologies, standards of what counts as appropriate teaching practice, and assessment- proficiency and competence requirements. More importantly are questions of curriculum- publishing companies tend to be Anglophone, and attitudes toward English and cultural sensitivity to other ontologies and ways of thinking. See English as a Lingua Franca.