波斯尼亚语
He is best known for his contribution to the standardisation of the Bosnian language. His best known works are "Orthography of the Bosnian language" (Pravopis bosanskog jezika), "The Bosnian language" (Bosanski jezik) and "Grammar of the Bosnian language" (Gramatika bosanskoga jezika). Characteristics of this spelling is equidistance towards the Croatian and Serbian spelling and morphological prescriptions, and expressions that are held for the typical Bosnian norm (formalisation of the phoneme "h" in certain words in the Bosnian language as seen in the words me"h"ko, la"h"ko, ka"h"va, ma"h"rama). 2018, in the new issue of the "Orthography of the Bosnian language", Halilović accepts expressions without the phoneme "h" due to their prevalence in language practice. He was criticized for that by Bosniak prescriptivists and defended by other linguists.