To manage translated collections we've created a special option. You can check it by clicking the language button above the collections. By default, it will display the original language of the store.
Click on it and choose the desired language. Collections, translated into this language, will appear. Here you will see info about the separate collections. For example, their status: translated, partial (partly translated), not translated. Manage them according to your needs.
Also, it's a very comfortable feature to search for translated collections by their names. In the search field enter the name of the collection you want to find in the selected language. Choose the item you want to manage and make your changes.