: Ensure the "bit-ness" (32 or 64 bit) matches your Office installation (check via File > Account > About Word Installation
To add Portuguese (Portugal) proofing to your existing Office 2016 installation: Language Accessory Pack for Microsoft 365 proofing tools office 2016 pt-pt
If you’ve installed Microsoft Office 2016 but find that your spell check, grammar check, and thesaurus are missing for Portuguese (Portugal), you likely need to install the specific pack. : Ensure the "bit-ness" (32 or 64 bit)