we have always stayed in touch with the people around FoodSharing and also Yunity, the ones with the Karrot mapping platform.
To answer your question: We started as a mainly German-speaking community, but wrote documentation and software from the beginning in English. It is the lingua franca of computing. It is important to consider internationalisation (I18N) from the beginning, which is not just the translation of words in the interface or in the content, but also the localisation for different time and number formats, etc.
Do you know when this gathering is supposed to happen?