Finding a proper version of the FIFA 18 mod for the (specifically in MAI format) can be tricky because FIFA 15 was the last official entry for the handheld. Most "FIFA 18" titles on the Vita are community-made mods. Key Details for FIFA 18 Mods
Ensure your PS Vita system language is set to English in the System Settings . FIFA 18 PS VITA(USA) (MAI) English
If you have a version that supports multiple languages, you can usually adjust it through the following steps: Finding a proper version of the FIFA 18
These mods typically update the rosters, kits, and UI of FIFA 15 to reflect the 2018 season. How to Change Language Settings FIFA 18 PS VITA(USA) (MAI) English