This is a compilation of all the eerie announcements that sporadically play in Alterna. Listening to the ripped audio without the reverb added ingame, you notice that it's actually English speech!
For this video I tried to transcribe as much of the sentences as possible.

0:00 Announcement 1
0:20 Announcement 2
1:15 Announcement 3
1:42 Announcement 4
2:15 Announcement 5
2:45 Announcement 6
3:10 Announcement 7