According to fansite TreeOfSaviorGame.com, CEO of IMC Games, Mr Hakkyu Kim, has provided an update for the international test of Tree of Savior. IMC Games is currently looking at overseas service providers for the international test server, with Amazon Web Services mentioned as one of the candidates. I am guessing this will be temporary until the regional publishers launch the game.
Currently supported languages include English, Chinese, Japanese, Korean, Portuguese and Spanish. I am not sure if all these languages are currently worked on at the same time, but the core language should be English. IMC Games is working to implement Facebook and Google+ logins, and the international test schedule should be revealed after Closed Beta 2 is completed in South Korea.