Answer 1

https://www.sololearn.com/Discuss/805417/windows-app-store

It seems that sololearn is working on adding more lessons in its android app that it has ignored the other updates. Some sololearners on android apps requested to have versions with different languages, but they claim getting no reply from sololearn.

You can either
-send a mail to [e-mail] to request for updates on windows, or
-find alternatives for sololearn on windows store like khan academy:
http://www.appsfuze.com/applications/windowsphone.reference/khan-academy,2203
https://khanviewer.codeplex.com/

Answer 2

SoloLearn has been extremely dishonest with your followers, closing educational Windows Phone apps for download. It can also stop the updates, but leave courses for download. Please give the option to download the course JavaScript and jQuery in Windows Phone.