Sharing the vocabulary list with other users and compete with them !
Thank you for your feature request!
You can already share your vocabulary with friends by exporting your fullk vocabulary or selected words (have a look on how to do it here: https://support.wokabulary.com/article/33-export-words-on-the-iphone-or-ipad)
We will add some more elements highlighting achievements and progress to the next version. If you do have any specific ideas for competitions, feel free to share!