The impact of subtractive bilingualism
By Martin Kindness

As the desire for English-medium education continues to grow worldwide, international schools continue to open. Many are unrecognisable as the original model: a facility catering for an English-speaking expatriate population. Indeed, some are home to significant, even dominant, numbers of host country nationals. Albeit to varying degrees, most will be characterised by the ethnic diversity of their student bodies compared to schools in the state system.


Ethnic diversity is celebrated in international schools, which typically will have policies stating their commitment to developing their charges’ international-mindedness, readiness for global citizenship, and bi- or multilingualism. The International Baccalaureate (IB) exists to help schools achieve such aims through, among other initiatives, purposively designed curricula and it was in an IB school that the origin of this article lies.


What subtractive bilingualism looks like

A conversation with the parents of an English language learner (ELL) who wanted their child to do English A rather than English B in the IB Diploma Programme highlighted an issue I’d first become aware of some twenty years previously. On that occasion, Thai students in an international school in Bangkok suggested that, though their native tongue was the one they felt most comfortable in conversationally, they were uncomfortable about the prospect of studying degree courses in it at one of the leading local universities. Academically, English had become their strongest language, even though most of the students still fell some way short of native-speaker levels of oracy and literacy.


Notwithstanding his parents’ preference for English A as, in their view, a more secure pathway into an English-medium university, the boy’s English teacher thought English B to be the more appropriate option for him. His English was serviceable, but there were gaps in his vocabulary and issues with grammar and syntax that English B, as a language acquisition course, would better address. Could he take his native Japanese as an A language? No, he couldn’t, unfortunately. Having ceased to maintain it after entering international schooling some three or four years previously, their son was ill-equipped to take Japanese as, in effect, a first language. As with the Thai students, English, despite its relative modesty, had supplanted his mother tongue as his strongest language in an educational context, and, in effect, he didn’t have a readily recognisable A language in a system that expected him to do so.


A term exists for the situation in which a student learns the language of instruction to the detriment of their first language: subtractive bilingualism.


Addressing subtractive bilingualism

Subtractive bilingualism is not one that seems to feature prominently in international school discourse, perhaps because of beliefs that English, as the language that unites core curriculum subjects and other content areas, has to be first among equals. Indeed, it is not unknown for schools to ban the use of students’ first languages in an attempt to promote an English-speaking environment in which, it is thought, fluency in the target language will follow. Following this lead, parents of ELLs sometimes make their homes ‘English only’.


If the fundamental aim of education is to extend rather than restrict a child’s capabilities, then the phenomenon of subtractive bilingualism deserves a lot more attention than it often gets, since it represents the latter outcome. And, notwithstanding intuitive faith in the ‘monolingual principle’ referred to above, which prioritises usage of the target language as the means of acquistion, subtractive bilingualism often means restricted ability not just in the first language (L1) but also in the second language (L2), which in turn threatens to undermine academic success more generally.


Jim Cummins was one of the early proponents of the theory that competence in one’s first language helps secure competence in one’s second language, with the converse – limitations in L1 compromising progress in L2 – also being the case. In particular, he argued, mastery of cognitive academic language proficiency (CALP) in L2 requires the high level skills that characterise it to be present in L1,  and without CALP students cannot be considered fully in command of language that, in tandem with subject content, becomes increasingly abstract and complex as school years go by.


His hypotheses have since been supported by research into the interrelationships between languages and how they contribute to or detract from academic progress, and call for a pedagogic approach that maintains and develops students’ first language alongside English, ideally from an early age. In Dulwich College China and Singapore, dual language learning – specifically of Mandarin and English – is a fundamental component of student development in kindergarten, while Vienna International School was among the first to recognise the benefits of additive bilingualism and has long had an extensive mother tongue programme for its ELLs. The approach in these examples is institutional in nature, not dependent on a few well-informed teachers acting individually.


Valuing mother tongue and culture

Besides the cognitive and academic advantages additive bilingualism bestows on students, it is important that their mother tongues, and the cultures they come from and reflect, are shown to be valued by a school which claims to be international in more than mere name. Otherwise, there is a threat to ELLs’ sense of identity and to their social and emotional wellbeing. More than language can be lost.


All this said, to implement and maintain programmes in which students’ L1 is afforded dedicated curriculum time is difficult for all schools to do, particularly those with an abundance of mother tongues in their student bodies. There are, however, a range of practical steps to be considered. Among them are:

  • The encouragement of student pre-reading of course content in L1, and the provision of key vocabulary translated into L1.

  • The availability of reading material in multiple languages in school libraries.

  • Allowance of L1 use in classrooms, such as in the planning and drafting of written work, or in brainstorming activities.

  • Where possible, the employment of bilingual teaching staff to work with classroom teachers and students.

  • The employment of L1 teachers to provide language arts lessons in L1 outside the regular curriculum.

  • In English-medium schools in countries where L1 is a compulsory curriculum subject, the provision of protected planning time between the L1 department and EAL team in order that shared learning objectives in related units of work might be agreed.

  • Communication with parents about the benefits of additive versus subtractive bilingualism, and advice given on how they might support the continued development of their children’s first languages at home in service of additional language learning and academic progress.

A solution: content and language integrated learning

An alternative to dual language initiatives in mitigation against the dangers of subtractive bilingualism is a robust approach to content-and-language-integrated-learning (CLIL). In CLIL, the language of instruction is primarily English, but planning, teaching and assessment focuses not just on subject content but its associated language, too, ideally with EAL and subject teachers working closely together. The aim of CLIL is for ELLS to attain CALP through the study of language in context, of which the curriculum is an automatic provider, rather than at a remove, as is often the case in more traditional EAL programmes.


Ultimately, it is the nature of the school which will determine its actions. Inaction, though, by failing to translate philosophies and policies into practices, is not an option, not when so much rides on language learning in our schools. The rewards for learners are considerable. Equally, there are risks.


The philosopher Ludwig Wittgenstein wasn’t speaking about international school education when he famously said, “The limits of my language mean the limits of my world.” He might well have been, though.

Martin Kindness is an EAL Teacher at The British School in Tokyo

Martin can be contacted on Linkedin

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