Here is the full list of all 24 Learn Japanese To Survive! Katakana War achievements.
Clear the game.
Maximize all character's affection levels.
Unlock the power of the Crystarium
Try 3 different types of seafood.
Complete all 20 side quests.
Complete 15 side quests.
Complete 10 side quests.
Obtain the ultimate sword.
Complete lesson 10.
Unlock the potential of corn soup.
Complete lesson 9.
Complete lesson 8.
Complete 5 side quests.
Complete lesson 7.
Complete lesson 6.
Maximize a character's affection level.
Complete lesson 5.
Visit the Challenge Castle.
Complete lesson 4.
Complete lesson 3.
View a character's affection event.
Complete a side quest.
Complete lesson 2.
Complete lesson 1.