A Comparative Corpus-Based Study of Vocabulary, Sentence Structure, and Tense-Aspect Usage in the Dialogues of “Global Success” and “Family and Friends” for Vietnamese Primary Learners.

Abstract

This study presents a corpus-based comparison of dialogue content in two primary English textbook series widely used in Vietnam: Family and Friends and Global Success (Grades 3–5). Examining three dimensions of linguistic input—vocabulary range, sentence complexity, and tense-aspect usage—the study analyzes a corpus of 1,143 utterances drawn exhaustively from nine Student’s Books. Utterances were analyzed using AntConc 4.3.1, a Moving-Average Type-Token Ratio (MATTR) procedure, and manual coding of tense-aspect and communicative functions. Results indicate that Family and Friends offers a wider lexical range, longer and more structurally diverse utterances, and a broader functional deployment of verb forms. Conversely, Global Success concentrates on the Present Simple, repeats a limited set of question-and-answer patterns, and confines the Past Simple almost exclusively to asking and answering. Interpreted through Systemic Functional Linguistics and Leech’s tense-aspect theory, the series represent complementary pedagogical designs: one oriented toward communicative breadth and the other toward patterned consolidation. These findings provide teachers, materials developers, and curriculum designers with an evidence-based foundation for textbook selection and adaptation in the Vietnamese primary EFL context.