Linguistic alternation is an essential choice for diversifying the teaching languages of non-linguistic subjects. And for some researchers, reasoned linguistic alternation facilitates language learning, the construction of disciplinary concepts as well as the development of transversal skills (Moore, 2001).
However, this alternation can occur at several levels and in different ways. Thus, research has distinguished between three levels: micro, meso and macro (Duverger, 2007a; Gajo, 2007, Reynal de Saint Michel, 2015) while other studies have differentiated intersentential alternation from intrasentential alternation (Gearon , 1997).
Jean Duverger (2007a) found that when deciding to teach a non-linguistic subject (DNL) in two languages (i.e. a foreign language in addition to the first language), the teacher of this subject works with his students, at the same time, improving the learning of the second language and the construction of the concepts of his discipline.
But achieving this dual objective "is cognitively complex", as Causa pointed out, because when teaching a non-linguistic subject in a foreign language, the language serves as a medium for "learning non-linguistic content while by improving foreign language proficiency” (2009, p.180).
Types of language alternation
What are the different types of language alternation possible? There are three different types of alternation
The macroalternation is the fact that, in the annual program of a discipline, certain didactic units will be taught in French while others will be taught in the main language of the school establishment; it is the overall planning of the use of languages for the teaching of the subject over the school year. The rhythm of the macro-alternance is not necessarily regular throughout the school year: it will depend on the subjects. L. Gajo (2005) characterizes macro-alternance in this way: it "(...) relates to didactic planning, to the organization of the curriculum (...)".
Meso-alternation or sequential alternation is the passage from one language to another between two large portions of coherent didactic interactions. It is set up throughout the didactic unit or in the same course, depending on the documents, experiments and observations, research, syntheses (Duverger, 2007).
Microalternation is the fact of punctually making reformulations, explanations in the other language within a sequence that is worked in one language by following the programming of the alternation carried out for the year. L.Gajo characterizes it as "a local discursive practice".
Criteria for language alternation
To ensure the purpose of facilitation in the transmission of disciplinary content, the alternate use of the two languages must be carried out taking into account criteria of various kinds:
Linguistic alternation: example of the Moroccan context
For example, the Moroccan context is a multilingual context where several languages and dialects coexist in the different spaces of collective life, the pupil is required to learn three standardized languages from the first year of primary education. Thus, from the age of 6, Moroccan pupils begin learning Arabic, Amazigh and French.
In order to reinforce the mastery of foreign languages, the Moroccan Ministry of National Education has decided to generalize the teaching of mathematics and sciences (physics, chemistry and life and earth sciences) in French for the international course ( French option) in middle school and high school from the start of the 2019/2020 school year.
In addition, the new linguistic engineering of the school system provides that certain contents or modules of non-linguistic disciplines (in particular scientific disciplines) are taught in French and/or English, whereas in lower secondary school the teaching of these is performs in French in addition to the Arabic language which remains the main language of instruction in these two cycles.
In short, the transition from one language to another must make it possible "to facilitate the acquisition of disciplinary concepts and new linguistic knowledge, to expand the content by interweaving documents in different languages and to diversify the entries" (Béliard and Gravé-Rousseau, 2010).