The language of Ayapaneco has been spoken in the land now known as Mexico for centuries. It has survived the Spanish conquest, seen off wars, revolutions, famines and floods. But now, like so many other indigenous languages, it's at risk of extinction.
There are just two people left who can speak it fluently – but they refuse to talk to each other. Manuel Segovia, 75, and Isidro Velazquez, 69, live 500 metres apart in the village of Ayapa in the tropical lowlands of the southern state of Tabasco. It is not clear whether there is a long-buried argument behind their mutual avoidance, but people who know them say they have never really enjoyed each other's company.
"They don't have a lot in common," says Daniel Suslak, a linguistic anthropologist from Indiana University, who is involved with a project to produce a dictionary of Ayapaneco. Segovia, he says, can be "a little prickly" and Velazquez, who is "more stoic," rarely likes to leave his home.
It sort of reminds me of an old joke about two Jewish guys stranded on a desert island who build their own temples and refuse to set foot in the other one.