The patch, which can be downloaded from GameBanana, uses files left in the Japanese version of the game. You can check out the English version of the game in action in the video below.
The first entry in the celebrated series by Square Enix was released on Nintendo 3DS in Japan only back in December 2014. It originally launched as a first print bonus for Final Fantasy Explorers before getting released separately in January 2015. Alongside 3D support, this version of the game includes all the additional content found in the PSP and GBA releases. The original Final Fantasy has been recently remastered as part of the Pixel Remaster series. You can learn more about it by checking out my review.