You find some graffiti. It reads: "The pouch lives in the 3x4 inverted moniker." It appears to be signed by "OyouOrtut␣␣␣" And there is also "ariibeaobvtn abbrev." What does this mean?
Draw a grid, three across, 4 down (3x4). Abbrev. is self-referential. If you wrote "abbreviation" like this: you can read it as "ariibeaobvtn". Now write the signature (moniker), in the same way as "abbreviation". It should look like this: . If you read it as the gibberish version of "abbreviation", it becomes "out you Ort ". Ort is German for "place". Translate the English to German, and vise versa (inverted). This gives "aus Sie place". "aus Sie" → "ausSie" → "Aussie". This thus means "Aussie place", or Australia. Kangaroos have pouches, and live in Australia. Thus, this OyouOrtut␣␣␣ guy is saying "Kangaroos live in Australia"!
I'm pretty sure this is
Jeroo, the programming language.
The pouch lives in the 3x4 inverted moniker.
In Jeroo, you program a Kangaroo to move around a grid (like a 3x4 grid). Pouch here refers to a Kangaroo. I'm not entirely sure what the meaning is behind the name though.