If you need to host Google fonts on your own and you also need alternative formats than .ttf to support multiple browsers you can download them from Google with this procedure (found on Stackoverflow). The .ttf files can directly be downloaded from Google fonts using their download link:
- Go to Google fonts and select your desired font.
- Open the displayed usage URL (e.g. fonts.googleapis.com/css) in Google Chrome => The browser specific download URL is displayed (e.g. fonts.gstatic.com/s/opensans/v13/K88pR3goAWT7BTt32Z01mxJtnKITppOI_IvcXXDNrsc.woff2)
- Open Developer Tools (F12), press ESC, go to Emulation => Network: On "Spoof User Agent" select the browser you want to have support for (e.g. IE 9).
- Reload the URL from 2. You will now see (another) browser specific Download URL (e.g. fonts.gstatic.com/s/opensans/v13/cJZKeOuBrn4kERxqtaUH3T8E0i7KZn-EPnyo3HZu7kw.woff)