Yes, you can install additional fonts, but these fonts are not like the ones used in the Windows OS. They're special fonts that have been created to work exclusively with this application. You won't have the possibility to select the fonts installed in your OS. However, it was specified on some websites that the application is compatible with most of the international fonts that are used in this field of work. Go to Help > Contact and get in touch with the developer. He should provide all the necessary fonts.