Cette thèse a pour objet d’étudier les compétences discursives chez les étudiants nigérians de 3e année de FLE et l’influence des modes de discours culturels dans leurs productions de textes argumentatifs. Nous avons également étudié les représentations des enseignants sur les écrits des étudiants ainsi que leurs pratiques d’évaluation. Pour cela, nous avons présenté le contexte sociolinguistique de notre public, la politique linguistique du Nigeria ainsi que la place des langues nationales et étrangères dans le pays. Nous avons étudié les copies des étudiants à l’aide de la méthodologie issue des études de la linguistique textuelle et des écrits plurilingues. L'enquête de terrain s'est déroulée au Village Français du Nigeria (VFN) à Badagry. Nous l'avons organisée en trois étapes en nous appuyant sur le questionnaire et l'entretien exploratoire (destinés aux élèves et aux enseignants de français) et sur l’observation non participante. Les principaux résultats ont démontré une forte influence des ressources plurilingues et culturelles dans les productions écrites des étudiants. Or les enseignants ne tiennent pas compte des compétences plurilingues des étudiants dans leurs évaluations des copies mais se concentrent plutôt sur les aspects linguistiques et les fautes grammaticales. Partant de ces constants, nous avons jugé nécessaire de proposer une grille d’évaluation ainsi qu’une séquence didactique qui portent sur les notions d’argumentation et les composantes textuelles à travers des textes divers. Ces exemples pourraient être utiles pour les enseignants et les étudiants dans leur apprentissage. / The aim of this thesis is to study the role of the multilingual competence of third year undergraduate students of French as a foreign language in Nigeria. We also studied the teachers’ perceptions of the students’ essays as well as their assessment practices. To achieve this, we presented the sociolinguistic context of the students, the language policy of Nigeria as well as the place of national and foreign languages in the country. We studied the students’ scripts using textual linguistic and multilingual writing methodologies.The field work took place at the Nigerian French Language Village at Badagry. It was organised in three stages using questionnaires and exploratory interviews with the students and the teachers, and non-participatory observation in the classroom. The main results showed that the students have their perceptions of argumentative writing and multilingual competence. The teachers do not take into account the multilingual competences of the students but focus instead on linguistic content and errors in the scripts. We also observed that the teaching of argumentative writing remains at the theoretical level and unrelated to the students’ experiences and context. Following these observations, we deemed it necessary to propose an assessment grid and a didactic sequence on teaching argumentative essays and its textual features using different text genres. These examples could be useful for both students and teachers.

The main purpose of this study is to observe the L2 acquisition effect of studying abroad during approximately four months in Swedish non-native speakers (NNSs) of Spanish with respect to their use of multi-word structures (MWSs) as compared to native speakers (NSs). In addition, this evolutionary study has a secondary aim which is to see the effect of the activity type on the amount and distribution of the MWSs encountered.    This study shows positive effects of a study abroad period in L2 use and, particularly, regarding MWSs. It has been shown that the amount and variety of the NNSs’ MWSs have increased during their stay in Spain, and that the differences with the NSs in the use of MWSs have diminished or even, in some cases, disappeared. It is notable the improvement in the NNSs’ discourse competence. The study also shows that the type of task affects the results. Thus, the negotiations that contain specialised vocabulary which participants are familiar with, yield a higher token frequency of MWSs among NSs and NNSs than the focus group discussions, more free and spontaneous. The negotiations also yield a higher token frequency of conceptual MWSs, especially noun phrases, because of the specialised vocabulary, more complex and subject to greater nominalisation.The focus group discussions have a higher token frequency of own-management MWSs than the negotiations, which is attributed to a higher communicative pressure. On the other hand, the token frequency of interaction management MWSs is higher among the NSs in the mixed group discussions compared to those with only NSs, as a result of collaborative interaction between the NSs and the NNSs. Individual differences among NNSs have also been observed and five profiles have been distinguished. These differences decrease in general at the end of the stay, which also indicates a positive development. There is a positive development in all profiles, which is reflected in significant changes in the amount and variety of the MWSs, their distribution in categories or in the emergence of more complex types. A direct link has also been observed between communication orientedness, participation in conversation and a positive development.