Here is the full list of all 20 Silent Tweets achievements.
Level 20 Started
Level 19 Started
Level 18 Started
Level 17 Started
Level 16 Started
Level 15 Started
Level 14 Started
Level 13 Started
Level 12 Started
Level 11 Started
Level 10 Started
Level 9 Started
Level 8 Started
Level 7 Started
Level 6 Started
Level 5 Started
Level 4 Started
Level 3 Started
Level 2 Started
Level 1 Started