Is immersion the best way to teach a new language to adults?

Many language schools focus on 100% immersion, and even require their teachers to use the target language exclusively. For example, not long ago I interviewed for a position teaching English to business professionals in Colombia, and I was told that I must not use any Spanish in the classroom … that I must teach the entire time in English. Is this the best way to teach adults?

No it is not, and especially not for beginner students.

So, why do language schools focus on immersion? I suspect that many use full immersion out of necessity and not by design because they simply don’t have teachers that can speak both languages effectively, such as the many Spanish language schools in Latin America that sell their programs to native English speakers; their Spanish teachers cannot speak English, so they sell the benefits of 100% immersion in Spanish. Or, it could be that some language schools who do corporate training are required by their corporate clients to provide 100% immersion in the target language. Finally, it is possible that the majority of language learners insist on full immersion. Whatever the reason(s), full 100% immersion for all students regardless of language level is not the most effective approach to teaching a new language to adults.

I am not a linguist that has studied language acquisition, however I have done a fair amount of research on language learning methods. Also, I began learning Spanish at the age of 48 … and having spent 7 years on this process, I know firsthand at least what works best for me. Moreover, I have been teaching English as a second/foreign language (ESL/EFL) for several years to adults, and it is clear to me that complete immersion can at times be very ineffective and discouraging to students. So, I would like to offer a better and more nuanced approach to teaching a new language to adults.

Language immersion should be tailored to the language level of the adult students. For instance, in a class of beginners with little or no exposure to the English language, it would be counter-productive to speak English the entire time while trying to teach them the alphabet, basic words and verb tenses, etc. If I were to speak English the entire time, most of what I said would not be understood. Some will say that my speaking the entire time in English is a good way to tune the ears of the students to hear English, but I would argue that students can get their ears much more effectively tuned outside of class by listening to English language audio, by watching video on TV and the internet, or by having conversations with native English speakers. Advanced language students, however, would obviously benefit from complete immersion in the classroom, and intermediate students are somewhere in-between. Below is my proposal for the relative level of immersion that should be applied to students at different levels of language acquisition.

The Common European Framework of Reference for Languages (CEFR) is a widely used guideline for assessing the aptitude of foreign language students all over the world, and it lists the following 6 levels:

Level A1 – Beginner
Level A2 – Elementary
Level B1 – Intermediate
Level B2 – Upper Intermediate
Level C1 – Advanced
Level C2 – Mastery

Based on my research and personal experience (both teaching English and learning Spanish), I recommend that at each higher level more immersion can be applied in a classroom of adults. The level of immersion that I recommend for adult English language learners at each level is as follows:

Level A1 – Beginner – no more than 60% immersion
Level A2 – Elementary – no more than 70% immersion
Level B1 – Intermediate – no more than 80% immersion
Level B2 – Upper Intermediate – no more than 90% immersion
Level C1 – Advanced – 100% immersion
Level C2 – Mastery – 100% immersion

I have taught English to adult native Spanish speakers for many years, and I have also taught English at universities in the USA to international students to prepare them to pass the TOEFL and IELTS exams and to enter university studies. Based on my experience with these (and other) internationally recognized aptitude tests, adults do not reach the B2 upper intermediate level until they can comfortably use about 50% of the verb tenses effectively (including past, present, future and conditional verb tenses). In English there are 16 verb tenses, and the average native English speaker uses most, if not all of them, on a regular basis. However, in my experience, many adult English language learners plateau at the B1 intermediate level, and stick to using no more than about 4-5 verb tenses on a regular basis … and even then, a B1 level student does not use those 4-5 most common verb tenses accurately and comfortably all the time. So, when I am teaching English to intermediate level native Spanish speakers, I have found it very helpful to clarify grammar points and in particular verb tenses by speaking to them in Spanish when necessary in order to enhance the learning experience. For example, once I show them how a specific English verb tense compares to the same basic tense in Spanish, they understand the lesson much quicker (or perhaps for the first time) and we can move on to practicing the language and to deepening their language aptitude.

The English language school in Colombia that interviewed me has corporate clients that want to improve the English skills of their employees. However, if their employees are anything like most of the adults that I have taught through the years, it would be counter-productive for me to use only English in the classroom (unless, of course, I am given all advanced students). Instead, after I have measured the overall level of the students, I should apply the appropriate level of immersion according to the scale that I have detailed above. If 100% immersion in English is required, it would likely lessen the effectiveness of the language learning environment and reduce a client’s return on investment.

Any thoughts?