When using web fonts, it is recommended that you double check all fonts you use support the language that they are going to display. If the font you're using in your design does not support characters of the language used in your design, there can be errors in displaying the text.

To check language support, go to fonts.google.com. Using the filter options on the top left of the site, you can filter the fonts available by their supported languages. For the example below, I filtered Chinese (Simplified). 

An example of a font family that supports multiple languages and non-Latin characters is the Noto family. You can find Noto in the font selection dropdown.