1) Create a .txt file with the name od the title id of your game, for example "0004000000030d00.txt" for EU Nintendogs, check that the filename matches with the title id
2) INSIDE that you need to write: USA EN and save your file
3) Create a folder named "locales" inside your "luma" folder that is in the root of your SD.
4) Paste the file we just created in the "locales" folder
5) Power up your console pressing the Select button at the same time, Luma configuration menu should boot.
6) Check the option "Allow region and lang emulation" and press start
7) Run your game.
REMEBER all the names goes without the quotations. Tell me if you face any trouble,