Since the 1960s, legal writing pedagogy in the United States has been heavily influenced by the plain English movement, which largely discourages the use of legal jargon and overly complex syntactic structures in legal documents. While these efforts to democratize legal English are laudable, it is unclear whether plain English practices can accommodate the needs of multilingual, foreign legal writers who have not yet acculturated to the U.S. legal discourse. Using mixed-effects modeling, this study tracks the development of syntactic and lexical complexity in 246 hypothetical legal essays written by 31 international Master of Laws students enrolled in a year-long legal language course. Results show that after one year of instruction, students demonstrated a significant increase in the use of nominalizations and sophisticated vocabulary. However, their sentences became notably shorter, and there was a marked decrease in the use of noun phrases with pre-modifying adjective within semesters. We discuss the intersection between plain English and academic writing practices and their impact on second language (L2) writers’ developmental trajectories. We also highlight important caveats to consider when implementing plain English pedagogy in legal language classrooms.

This longitudinal case study tracks the development of four second language (L2) writers’ skills in hypothetical legal writing in a year-long legal language program. Drawing on the system of Engagement from systemic functional linguistics, the study analyzes how L2 writers engaged different legal voices and advanced their arguments via three discursive strategies: dialogic expansion, contraction, and justification. An examination of the Engagement resources the writers deployed in 32 essays illustrates their diverse developmental paths and highlights the linguistic choices that reflect the variation in their development. I discuss the influence of initial L2 proficiency and model essays on L2 writers’ trajectories and the distinct challenges these writers faced in maintaining a consistent argumentative position. I argue that the system of Engagement is a useful analytical framework for understanding the linguistic choices L2 legal writers make as they work toward the communicative goals of the target legal genre.

In the past three decades, the construct of second language (L2) writing complexity has been theorized and refined in both second language acquisition (SLA) (Crossley, 2020; Housen, De Clercq, Kuiken, & Vedder, 2019; Lu, 2011; Norris & Ortega, 2009) and Systemic Functional Linguistics (SFL) research (Byrnes, 2009; Ryshina-Pankova, 2015; Schleppegrell, 2004). The general consensus is that lexical and syntactic variations are regarded as signs of advanced academic writing. The contemporary legal writing pedagogy, however, is informed by the Plain English Movement (Benson, 1985; Dorney, 1988; Felsenfeld, 1981), which largely discourages the use of overly complex structures and “elegant variations.” The recommendation to use plain English in legal writing thus poses a challenge to the theoretical consensus in SLA and SFL research and raises a question about the conceptualizations and assessment of writing complexity in academic legal writing classrooms.

This dissertation consists of three interrelated studies and aims to address this contradiction by examining the development and assessment of writing complexity (i.e., lexis, syntax, and discourse) in 246 hypothetical legal essays written by 31 international (LL.M.) students over one year of legal language study at the Georgetown University Law Center. In Study 1, I used a structural, corpus-based approach and tracked the changes of 31 students’ lexical and syntactic complexity at six data collection points over one year and compared the complexity indices with those benchmarked by eight model essays. In Study 2, I offer an in-depth discussion of four students’ distinct developmental trajectories of discourse complexity, which I analyzed through the system of engagement (Martin & White, 2005) from the SFL perspective. Finally, in Study 3, I adopted a mixed-methods approach to investigate two legal instructors’ conceptualizations of writing complexity in the classroom setting.

Results showed that overall students were able to write with significantly more sophisticated words and, in the second semester, significantly shorter sentences, a pattern consistent with the pedagogical focus of the program. Additionally, the four individual trajectories of discourse complexity indicate that, even when starting with a similar proficiency level, some students constructed increasingly complex legal discourse by actively engaging different legal voices through dialogic expansion and contraction, while others only made marginal progress. Consistent with the instructors’ conceptualizations of writing complexity, structurally more complex essays were not necessarily of higher text quality. In fact, the instructors’ assessment of text quality was found to be influenced by a number of external factors, such as students’ performance in comparison to others and their academic progress in the program. I conclude by discussing additional insights that emerged from the dissertation, such as the boundaries between text modeling and plagiarism, as well as the role of text length in assessing timed writing. Finally, I call for a critical reflection on the pedagogical principles of Plain English and highlight the value of an integrated structural-functional approach to holistically understand the construct of L2 writing complexity in academic legal writing.