Here is the full list of all 21 Terra Alia achievements.
Finish the game
Finish the game in two different languages
Finish the game in three different languages
Finish the game in five different languages
Finish the game in all languages
Learn 50 words
Learn 100 words
Learn 200 words
Complete a Talent branch
Reach level 10
Complete 3 Dialogue Challenges with a perfect score
Equip Falco with 3 Transistor Cores
Unlock 10 lockboxes
Complete 10 ATM training exercises with a perfect score
Complete your first combat
Enter Focus Mode twice during the same combat
Recover 100 points of Health during combat
Fully equip yourself
Choose 3 correct words in a row during the Focus Mode minigame
Avoid combat with Arkel von Camp
Complete the tutorial