Autocad 2018 Language Packs Install - __link__
No. Language packs merely replace string tables (text). Performance impact is negligible (<0.5%).
If you have a valid Autodesk Account with access to AutoCAD 2018: autocad 2018 language packs install
For users without a current subscription, Autodesk's Language Manager (available for 2015-2019 versions) streamlines the process. autocad 2018 language packs install