Source sans pro and Libre Franklin Fonts not working for Bulgarian language

We are using "Source sans" and "Libre Franklin" fonts from https://fonts.adobe.com/ portal. We are using these fonts on non-prode url: https://feelyourbeatcom-preview.dev.pfizerstatic.io/test-page but the fonts are working for english language only and not for other language(Bulgarian).See screenshot attached for non-prode site. Please let us know if these fonts supports Bulgarian language or not? If yes then please provide us the steps to select the required language(Bulgarian) from the portal end.