In the UK, there is a service called RelayUK, and it's for the deaf and speech impaired. It's a free service and also has an app. You can type the entire conversation to the operator who will read it out to the person you're calling, or you can type out as little as you want. The relay operator can and most likely will type out what the other person is saying to you, unless you clarify, you can hear. I have no idea if it works internationally, but I don't see why it wouldn't.