This will redirect you to an Autodesk page listing available packs for older versions. Close AutoCAD completely before starting the installation. Run the downloaded .exe file to extract the files.
For specific 2021 variants, you can find dedicated download articles on the Autodesk Support AutoCAD 2021 Language Packs AutoCAD LT 2021 Language Packs AutoCAD Architecture 2021 Language Packs Language Packs Mac - Forums, Autodesk autocad 2017 french language pack 2021
Install the pack after the main software is already installed. 🛠️ How to Install Check your Account: Log into autodesk.com. This will redirect you to an Autodesk page