For Tier 2 and higher, the only tasks that count toward language are the partisan tasks and the group missions. You will get one point for the first partisan task or mission that you complete in a zone. You will get an additional point for completing an additional 3 of any combination of partisan tasks or missions in that zone for Tier 3 and 4 (2 points for Tier 2). Completing all 6 partisan tasks and both missions will get you an additional 1 or 2 points depending on the zone. The mercenary (kill) tasks for Tier 2 and higher do not gain you any language points.
i.e.
Tier 2
•Doing all of Sarith partisan tasks and missions = 5 points
•Doing 4 of any combination of partisan tasks or missions = 3 points
•Doing 1 partisan task or mission = 1 point
Tier 3
•Doing all of Rubak partisan tasks and missions = 3
•Doing 4 of any combination of partisan tasks or missions = 2 points
•Doing 1 partisan task or mission= 1 point
•Doing all of Beast Domain partisan tasks and missions = 3
•Doing 4 of any combination of partisan tasks or missions = 2 points
•Doing 1 partisan task or mission= 1 point
•Doing all of Resplendent Temple partisan tasks and missions = 4
•Doing 4 of any combination of partisan tasks or missions = 2 points
•Doing 1 partisan task or mission= 1 point
Tier 4
•Doing all of City of Bronze partisan tasks and missions = 3
•Doing 4 of any combination of partisan tasks or missions = 2 points
•Doing 1 partisan task or mission = 1 point
•Doing all of Pillars of Alra partisan tasks and missions = 4
•Doing 4 of any combination of partisan tasks or missions = 2 points
•Doing 1 partisan task or mission = 1 point
•Doing all of Windsong partisan tasks and missions = 4
•Doing 4 of any combination of partisan tasks or missions = 2 points
•Doing 1 partisan task or mission = 1 point
•Doing all of Sepulcher partisan tasks and missions = 4
•Doing 4 of any combination of partisan tasks or missions = 2 points
•Doing 1 partisan task or mission = 1 point