The preferences settings only relate to local services e.g. print services, upload to SmugMug etc. and has no bearing on the user interface.
Language selection is normally available during installation, at least with the Adobe downloads. I assume the version from the Windows store is the same unless it automatically takes the language of the OS.
The only way to find out is to uninstall the program and then download again from your purchases.
To download Photoshop Elements 2018 from Microsoft Store in your language, first confirm whether the language you want is supported by Photoshop Elements 2018 or not. To find the list of supported languages -> Goto Photoshop Elements 2018 page on Microsoft Store , then scroll down to see the list of supported languages(click "more" for entire list).
If the language you want is not in the list for supported languages, the your Photoshop Elements 2018 will always install in English.
If the language you want is in the list for supported languages, then follow the below steps to download in your language.
You have to change the language of your OS to be able to use the Photoshop Elements 2018 in your choice of language.
Apps from Microsoft store always install in your OS language. When you switch the OS language, your apps language also changes.
For this Download the Photoshop Elements 2018 and then change the OS language using below steps.
1) Goto Region & Language settings (Search for Region & Language settings in the search field)
2) Change the Country or region field to your choice from the dropdown menu.
3) Then Add the language which you want to add and click on language that you have added and goto options and then download the language pack.
4) After downloading, return to the Region and language window and set the language as default.
5) Then sign-out and Sign-in again for the changes to come into effect.
6) Now you can use the app is your own language.
Hope this answers your query.