Immersion problem: Some translations are not educational. Potential solution: Use view count for each word in the translation as motivation.
People like to work on projects that will impact millions even if the work can at times be rather unrewarding.
And so show people how much impact their translation is having using a view count for each word in their translation.
If their translation is poor, then many of the words will have small view counts as they will be changed quickly in the wiki process.
If their translation is good, then many of their words will surive the wiki process and potentially be seen by millions.
The sum of the view counts could be used to rank translators for the day, week, month, year, and all time.