25VNU Journal of Foreign Studies, Vol 36, No 4 (2020) 25 35 HETEROGLOSSIA ANOTHER SFG BASED APPROACH TO TREATMENT OF WORD ORDER AS A MEANS FOR EXPRESSING MODALITY IN VIETNAMESE Nguyen Van Hiep* Vietnam Institute of Linguistics| 9 Kim Ma Thuong Street, Ba Dinh, Hanoi Received 13 February 2020 Revised 26 April 2020; Accepted 18 July 2020 Abstract The paper first introduces heteroglossia – a development of Systemic Functional Grammar (SFG) in Hallidayan Systemic Functional Linguistics (SFL) school[.]