This is a custom block that you can use in your projects. Have your player choose their language via an "ask and wait" command and set the Language variable to Answer. Then, whenever you use a say command in your project, set Message to your message of choice and insert Message as the parameter of the say command. This will cause your message to be automatically translated into your player's language of choice. The player must be connected to the internet for this to work.
There is a bug at the moment which means you may need to click See inside in order for it to work.