There are two official paths to obtain the offline installer:

setup.exe /configure config.xml Office will now install the proofing tools without needing further internet access. Deployment Considerations

One of the most overlooked, yet critical, components is the .

For enterprise environments, administrators can also download ISO images of language packs and proofing tools from the Microsoft Volume Licensing Service Center (VLSC) .

You can try using the Microsoft Office Deployment Tool (ODT) to download and install the proofing tools. ODT allows you to download and install Office products, including proofing tools, using a command-line interface.