Speak in radio? Use speakers to communicate with those who speak at human audible levels.
They seem to emote via colors (green, blue, red), but get embarrased if you ask about it. When you talk to them they turn blue (focus? attention?).
They are in charge of the waste recycling area, and have a decent sense of what elements would be needed to create a radio. The waste was separated into metal, goo that smells like a paper mill, and everything else.
We were warned to avoid sudden movements and leave if any colors go three red, two green. They do not see us as anything but obstacles on their way to prey (metal?).
If you take things from the waste recycling area, they want replacements in terms of amount and not relative quality
Some are trying to convince them to act as guards as well as waste recycling.
May have been battlebots that escaped/were lost - never part of an ecosystem.