<p>ISO 24495-2 standardises plain legal language as an international benchmark; however, its implementation is hindered by the lack of clear evaluative criteria for assessing the clarity of wording, structure, and design in new legislation. Drawing on an ISO-inspired categorisation of these three dimensions, this study undertakes a structured examination of governmental policies from six major common law jurisdictions: Canada, Australia, Hong Kong, New Zealand, the United Kingdom, and the United States. Findings reveal both similarities and differences in standardisation patterns. The wording and structure dimensions demonstrate strong stability and convergence, particularly in micro-level features such as modal verb usage, whereas the design dimension exhibits significant variability, operating as adaptive supportive practices rather than compulsory requirements. Based on convergent principles in plain-language policies across six jurisdictions, this study constructs a Three-Dimensional Framework of Plain Language Principles in Legislative Drafting. This framework aims to promote the standardisation of plain legal language within common law traditions and provide a valuable tool for legal drafters seeking to align new legislation with ISO 24495-2. Furthermore, it is believed to offer practical benchmarks for civil law jurisdictions by translating laws into English for international audiences. Eventually, this study contributes to legal linguistics and language policy by elucidating the institutionalisation of plain-language policies across analogous legal systems.</p>