InterestExplorer uses the Facebook Marketing API to reveal interests that are hidden in FB's own interfaces like Ads Manager & Audience Insights.
One of the parameters we use when calling the API, is the so-called 'locale' (like en_us). While Facebook supports many languages, you'll get the best results when using English as the locale.
Yes, our software will also be able to return local interests when you specify a non-English locale - BUT it will always be a smaller number of results compared to when you select English.
Most of our users live in (or target) English speaking markets.