Do you care about international app coverage? 

If so, the language filter is a your new best friend! The languages filter enables you to see which apps care enough about traffic in the demographic related to the translation (language) to localize their app (e.g. an app translated to German cares about the German demographic). 

You can find it under the SDK filter in the iOS Appstore Apps directory: 

This filter enables you to see apps that have been localized to certain markets. For example, if you care about apps in Japan, then you could set "Japanese" in your language filter to find apps that have been translated into Japanese. If an app has been localized in Japanese, this shows that the developer cares about the Japanese audiences. We have learned that it takes a lot of time, effort and/or money to actively translate an app to other languages, so when a developer does this, they tell us that they heavily target such audiences. 

You can also go one step further to find apps that are available in certain languages, but not other. For examples, here are some apps that are available in Chinese, but not English or French: 

Because this is a boolean filter, you can apply multiple languages. If you want, you can exclude a language you've applied by clicking on the green box with the language, and it will turn red, and be categorized as "not including".