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TESOL, TEFL, ESL, ELA, SLL, ELL — Common Confusing Acronyms and What They Mean

“A TESOL Certification Program will introduce you to concepts in ELA that will enable you to teach ESL to ELLs.”

Confused yet? We wouldn’t be surprised if you feel a little lost; but don’t worry—you’re not alone.

If you’ve tried English language teaching before, there is a high chance that you’ve encountered these terms and acronyms. They can all be a bit overwhelming to grasp right away though, so let’s break them down so you can easily understand their definitions and differences.


It is perhaps best to start with the concept of ESL, which stands for English as a Second Language. Now hold up—first, we need to understand what is a “second language” or L2. It must imply the existence of a primary language or L1, right? Indeed there is; the L1 is also commonly referred to as the native language or mother tongue, which is the language you are first exposed to. You grow up using this language and expectedly become inherently fluent in it.

The L2 is typically learned after one has a foundation in the L1, or these could be acquired somewhat simultaneously, and bilinguals can eventually develop advanced or near-native proficiency in the L2 even if it is a foreign language. ESL is specifically focused on learning English as the L2 (or L3 or further), which is different from how you might teach a first language, since students are likely exposed to it and are using the L1 more often in everyday conversations.

ELA, meanwhile, refers to English Language Acquisition, and you probably won’t see it used very often in informal contexts. Language acquisition is a more technical term that encompasses the research and theories underlying how language skills are developed, regardless of whether that is the L1 or L2 or further language. These in turn guide the most optimal teaching methods and learning contexts to help students attain language proficiency in an efficient and comprehensive manner.


The next two acronyms, SLL and ELL, are a case of broad versus specific terminologies. 

SLL or Second Language Learner pertains to any individual attempting to acquire a new language, the L2, other than their mother tongue. This could cover essentially any language in the world that one is studying outside of the first language.

On the other hand, ELL or English Language Learners are individuals developing their English proficiency specifically, whether it serves as the L1 or L2. However, in most contexts, the term would usually be associated with learning English as the L2 or other language.


On the flip side, in the context of educators, the terms TESOL and TEFL stand for Teaching English to Speakers of Other Languages and Teaching English as a Foreign Language, respectively. Both of these simply indicate that English is being taught as an additional language.

The main, but ultimately minor, difference lies in how English is perceived and used. As a foreign language, it would be very rarely applied in daily contexts, as in the case of South Korea and China, in contrast to places where English is considered an official but not primary language, such as in the Philippines. TESOL is a bit more general in that sense, and a certification in this program can be equally sufficient for positions needing TEFL certifications.

TESOL and TEFL represent the practical side of ELA that involves applying the best pedagogical approaches to educate learners on the English language, including grammar, vocabulary and different competencies such as reading, writing, listening and speaking skills.

Now that you’ve got the basics down, head on over to our Advanced TESOL Program to learn more in-depth concepts on effective ESL teaching.