AutoCAD 2018 is a multi-language product. While the core software installation usually defaults to English, users can install additional Language Packs to display the interface, documentation, and tooltips in their preferred language.
If you are deploying AutoCAD 2018 language packs across an organization, follow these enterprise guidelines: autocad 2018 language packs
Language Packs are to download and use for all licensed users of AutoCAD 2018. You do not need a separate serial number to activate a language pack. It draws its license validity from the main AutoCAD 2018 installation. AutoCAD 2018 is a multi-language product
Language packs are add-on software components that localize the AutoCAD 2018 interface. For example, a user who installed English AutoCAD can install a German language pack to switch the user interface to German. Availability: autocad 2018 language packs