PWA stands for Progressive Web App. It is a web-based version of Outlook that can be installed as an app from the browser, but it still runs using web technologies instead of being a full desktop client.
For the two questions:
- Keeping country as Greece but Outlook UI in English (USA)
In Microsoft 365 apps (including Outlook), display language and regional/country settings are separate. The display language can be set to English while regional settings (such as date, time, and locale) remain Greek.
For Microsoft 365 apps on Windows, the display and authoring languages are controlled in Office Language Preferences:
- Open any Office app (for example, Word).
- Go to File > Options > Language.
- Under Office display language, make sure English (United States) is in the list.
- If it is, select it and choose Set as Preferred.
- If it is not listed, select Add a language (or Install additional display languages from Office.com in some versions), add English (United States), and then set it as preferred.
- Leave Windows regional settings (country/region) as Greece so dates, times, and other regional formats remain Greek.
This changes the Office UI (including Outlook) to English while keeping the system’s country/region as Greece.
Relevant behavior is described in the Office language settings documentation, where display and authoring languages can be set independently of the operating system and region.
- Proofing options in Outlook PWA
Proofing (spelling and grammar) in Microsoft 365 is controlled by the Office authoring and proofing language and by installed proofing tools:
- In any Microsoft 365 application, go to File > Options > Language.
- Under Office authoring languages and proofing, ensure the desired language (for example, English (United States)) is listed.
- If it is listed, select it and choose Set as Preferred.
- If it is not listed, select Add a language, choose the language, and add it.
- Check the status column:
- If it shows Proofing installed, spelling/grammar tools are available for that language.
- If it shows Proofing available, select the link to install the proofing tools.
- Restart Office apps so the change applies to Outlook as well.
If proofing tools for a language are not installed yet, a language accessory pack may be required. After installing the pack, the status should show Proofing installed, and spelling/grammar checking will work in Outlook (including PWA) according to the selected authoring language.
Additionally, the proofing language can be influenced by the Windows keyboard language. After adding a language pack and keyboard, the default Windows keyboard language can change the Word/Office proofing language; this also affects Outlook’s editor.
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