Microsoft Office does not typically offer a single "offline installer" specifically for Language Accessory Packs for individual users. Instead, the process varies depending on your version of Office and your user role. For Standard Users (Microsoft 365, 2021, 2019)

Behind the scenes:

• Language packs are essentially Windows Installer patches (.msp) or Click-to-Run (C2R) packages.
• For Click-to-Run versions (Office 2016, 2019, 2021, Microsoft 365), offline language packs are .img or extracted folder containing stream.x86.x64.*.dat and language-specific cab files.
• The installer modifies Office’s language registry keys and installs localized resources into:

  C:\Program Files\Microsoft Office\root\Office16\LANGUAGE
  

If you tell me which Office version and architecture you have (e.g., Microsoft 365 Apps 64-bit, Office 2019 32-bit), I can produce the exact configuration.xml and command lines for an offline install.

If you install offline, you may need to manually check for language-specific updates later. Common Issues & Tips Use the Office offline installer - Microsoft Support

Execution: Once downloaded, you can move this file to an offline PC via USB and run it.

1. Language Interface Pack (LIP) – A lighter, partial translation. Requires a base language (e.g., English).
2. Full Language Pack – Complete translation of the entire Office interface and tools.