This came from 2 of Jacksons Marvel figures, each has a set of stock sounds but they both also have a couple of phrases that they only say to each other. This link gives you an idea:
So I was thinking about how this could work with items that recognise each other and have something unique to say when they were in close vicinity. I was researching how it works, which I didn’t find but I did find a couple of other things that do something when triggered by something else. See Light sources triggering LED lights:
and these cool tiles, which do a whole lot more:
My thinking was that one device could trigger different things, say as you navigate a building or give you different information as you pass through an area. In that way it would be similar to Beacons but not relay on a mobile. It could be a badge for example.