Hit the bottom-left button on the title page (options), and then the sixth option can be moved left/right to change the language. If the font color is white instead of black and has really strange looking characters, that is actually a graphics card driver bug and not a foreign language at all - try updating your driver (or rolling back if the issue was caused by a recent driver update).

Thanks so much! It was the strangest thing, the language had changed to Portuguese for some odd reason despite never having opened the options menu. ¯\_(ツ)_/¯

Thanks again!