Windows 10: Windows changed the language. How did this happen?

I live in Japan but am running the English version of Windows 10. Today, my computer seems to have rebooted and has changed the interface to Japanese. A few icons on the desktop have gone as well, and the taskbar configuration has changed.


While I can reset everything to the desired state (of course this means unnecessary work, but I am not writing this question to vent), I am worried. What if Windows does this to me again? How can I find out what happened? How can I prevent this from happening in the future?

:)

 

Windows 8.1 update changed the language, can't change back

Maybe, these will help... it seems it is a common enough problem.

Language packs are no longer available after you upgrade to Windows 8.1

And, sort of the same here --> Add a language or keyboard

Quote from above MS web page:

Spoiler Download and install language packs
You'll need to download the language pack if you want to make a language your Windows display language (that's the language you see most often in Windows and apps).

• Swipe in from the right edge of the screen, tap Settings, and then tap Change PC settings.
  (If you're using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, click Settings, and then click Change PC settings.)
• Tap or click Time and language, and then tap or click Region and language.
• Tap or click a language that says Language pack available underneath, and then tap or click Options.
• Tap or click Download. The download process might take a while, depending on your PC and the size of the language pack.
  If you want to make this your display language, see the next section "Change your Windows display language".

Change your Windows display language
To change your Windows display language (that's the language you see most often in Windows and apps), first add a language, download and install the language pack, and then follow these steps.

• Swipe in from the right edge of the screen, tap Settings, and then tap Change PC settings.
  (If you're using a mouse, point to the lower-right corner of the screen, move the mouse pointer up, click Settings, and then click Change PC settings.)
• Tap or click Time and language, and then tap or click Region and language.
• Tap or click the language that you want to set as your display language.
• Tap or click Set as primary to move the language to the top of the list. If the language can become your Windows display language, you'll see Will be display language after next sign-in appear under the language.
• Sign out and then sign back in to finish.

And here is some more info --> Add Language Packs to Windows

 

unable to change the language of UI

Hello,

Thank you for your interest in Windows 10.

To assist you better I would like to know, what was the base language for your previous Operating system?



I would suggest you to follow the below steps and check if it helps.

Step 1: Remove the Existing language.

• 
  Press Windows + X on your keyboard.
  
• 
  Select Control panel.
  
• 
  Select language.
  
• 
  Click on the Option adjacent to the
  Existing language.
  
• 
  Click on remove under input method.
  

Step 2: Add English Language.

• 
  Press Windows + X on your keyboard.
  
• 
  Select Control panel.
  
• 
  Select language.
  
• 
  Click on Add language.
  
• 
  Add the English language from the given list.
  

If you want a language pack:

You may refer to the suggestions posted by Andre Da Costa on the following thread.

Can I change language in Windows 10 Home edition?

Hope this information was helpful.

 

Language change

Hi Peter,

It could be that the language pack is missing on your Windows 10 device. With this, we suggest that you try to add the language on your device. Here are the steps:

• Go to Control Panel.
• Select Clock, Language, and Region.
• Under Language, select Add a language.

You may also check the Change input methods on which language are currently installed on your device. You may also click Add a language on the
Change your language preferences window.

Let us know how it goes and feel free to get back to us if you need further assistance.