I'm trying to find an app that let's my daughter in the US speak with her grandparents in China. My daughter, who is only 4, only speaks English and her grand parents only speak Chinese (Mandarin and Cantonese). Her grandparents aren't super tech savvy, so we've mostly tried video calls through we chat (with awkward very basic chinese/english).

If anyone has any recommendations on apps that work across the great firewall, recommendations would be greatly appreciated!