Windows 10: PowerShell Install-Language fails

I've been trying to put together a PowerShell script to automate Windows setup, and among the things I want to configure is the system language. I've been using a VM to test things but unfortunately I've been hitting a roadblock pretty early on on this avenue since the Install-Language isn't managing to complete properly. Specifically, after running it and waiting a good few minutes for it to complete which I hear is normal—why does it take so long, anyway? I get hit with the following error:Install-Language : Language pack or features could only be partially installed.ErrorCode: -21464981

:)

 

KB4025339 Fails Install 0x80070564

Thanks
I am trying Eagle 51's suggestions now. Windows Update troubleshooter found a bunch of errors and fixed all but one.The update is trying to download KB4025339 again. I'll see what happens. At step one troubleshooter finishes with one error unresolved "Potential Windows Update Database Error Detected-Not Fixed". Windows update stalled at 0%.

At step 2 same troubleshooter error. The KB finished a new download failed to install.
Did step 3 KB has downloaded but fails to install.

If Eagle's suggestion doesn't work I'll try EdTittel's suggestion

Tried bothe Eagle & Ed 's suggestions - do not work. Anyone else?

I have noticed that the latest update for my nvidia drivers has failed to update. Wondering about that!

 

PowerShell or CMD command to add preferred language pack (Japanese) in Windows Settings.

From PowerShell admin, run:

• Install-Language ja-JP
  

Install-Language (LanguagePackManagement) | Microsoft Learn: Install-Language (LanguagePackManagement)

 

Typing language problem

Why is Use language list only showing UK, and not US as another option in view of the steps I have taken to install it and put it at the top of my list? What is the' language bar', referred to? I don't think I have ever seen it, or am not recognising it if I had. And why is Keyboard shown as English UK when Settings is opened?