Alright well I haven't seen anything like this around, didn't search too thoroughly either so if it's a repost my bad, I'll delete it.
I've seen a lot of people in my guild ask how to turn off the announcement of the achievement spam in guild chat, because it does get quite annoying. This guide will show you how to do just that. What this guide does not do is stop the announcement of your achievements, so if people have not done this they will still see the spam.
This is fairly easy to do and kind of obvious, but a lot of people don't know how to do it so here it is.
Step 1: Right click on your general tab, and go to settings.
A box like this should open up:
Now notice the text in the red rectangle. This is what causes you to see when other people get achievements.
Step 2: Just simply uncheck this box to turn it off, and hit ok.
Now if you don't want to see the emote of yourself getting an achievement you can turn this off as well.
Step 3: Right click on general again, and then go to settings. This time go to the Other pane.
Then uncheck the checkbox in the red rectangle. This will prevent you from seeing the emote that you or others make when you get an achievement.
That's all folks, pretty simple, hope it helps some people. Have a good day!