In order to decipher the Eridium Writings you need to obtain the Eridian Decoder which can be obtained by completing the Main Mission - The Great Vault.
Warning: Once you decipher them all the achievement might not unlock, to fix this, head to the Sanctuary and interact with the Eridian Slab in Tannis’s infirmary.
None of the Eridian Writings are missable! All can be translated after the story in free roam.
Video with all the Eridiun Slabs:
Timestamps:
Pandora
Pandora
11 Eridian Writings
The Droughts - Curiosity 0:00
The Droughts - Names of the Destroyer 0:36
Ascension Bluff - Gnaw 1:01
Devil′s Razor - Building Pandora (Part 1) 1:29
Devil′s Razor - Building Pandora (Part 2) 1:55
The Splinterlands - Lure 2:24
Carnivora - Feeding 2:54
Guts of the Carnivora - Mantle 3:25
Konrad′s Hold - Warrior 4:02
Only accessible during/after side quest “The Demon in the Dark”
Cathedral of the Twin Gods - Key 4:50
Destroyer′s Rift - Contained 5:23
Promethea
6 Eridian Writings
Meridian Outskirts - Witch 5:58
Meridian Metroplex - Braid 6:37
Lectra City - Hunted 7:01
Only accessible during/after Side Quest “Kill Killavolt”
Skywell-27 - Knotted 8:17
Atlas HQ - Burden 8:46
Neon Arterial - Deal 9:19
Athenas
1 Eridian Writing
Athenas - Purpose 9:57
Eden-6
8 Eridian Writings
Floodmoor Basin - Guardians 10:33
Floodmoor Basin - Tools 11:06
The Anvil - Consciousness 11:41
Jakobs Estate - Free 12:04
Voracious Canopy - Keen 12:27
Ambermire - Uncountable 12:57
Ambermire - Sleep 13:25
Blackbarrel Cellars - Change 13:54
Nekrotafeyo
4 Eridian Writings
Desolation′s Edge - Erased 14:23
Desolation′s Edge - Language 14:57
Only during/after side quest “Bad Vibrations”
Tazendeer Ruins - Side By Side 15:48
The Pyre of Stars - Crypt 16:38
