Flipbooks created with Next Flipbook Maker use the default flipbook toolbar language - English. If your readers come from different countries, you can add their languages to the flipbook toolbar, which makes it easy for them to read your flipbook.
Find Language Settings under Setting tab.
Click the round icon on the right side to open below window:
Choose the languages you want to add:
Readers can click the Switch Languages button to choose the languages they use.