I have selected the following ideas to implement in the extension :
1. Local Storage of most common words : Adding local storage for translations of the 1000th most common words will cover around 55% - 70% of all words encountered. This will save time as well as character limits.
2. Adding Viewport limits : Limiting the translation process to the current viewport will save time and character limits.
3. Translation without using API keys : Using Google Translate's free API for new users for easy on-boarding.
4. Better quizzing/testing features : On-the-go spontaneous quizzing feature will increase user interaction. Once the user has marked the word as "learnt", the word will be enabled for this feature.
5. Improving basic UI/UX of the extension : Adding HoverCards for viewing translations, adding controls to Pop-Up page, Adding Interactive Tours, Changing UI/UX of Options Page and Adding Badge to Pop-Up for displaying information