Of course, you can use the language settings feature of flipbook to re-setting language.
Here are steps in detail:
Step1: Start your Boxoft PDF to Flipbook software, and import Object PDF for conversion;
Step2: Click “Option” drop-down list on the menu, and select “Flash Language” bar
Step3: Select language from list (more than one selection at a time)
Step4: Click “OK” button to save language settings, and refresh your flipbook, you will find the language has been changed.