Once in a while, I've come across a dead soldier ingame whose backpack is sending out a message in Morse code. Is there anything that I can do ingame regarding decoding or interpreting these messages? I'm currently in Manchester, and I haven't found anything that would let me decode the Morse code ingame so far.
In addition to the dead soldiers, there's usually a morse code message playing on the pause screen that changes on each level.
There doesn't seem to be any way in-game to decode these messages. They are just a tiny bit of extra story/plot color to the game, and don't really give you any gameplay hints or tips.
There's a complete list of the codes and their decoded messages on the Resistance Wikia.