"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.
The dictionary is part of a race against time to revitalise the language before it is too late. "When I was a boy everybody spoke it," Segovia told the Guardian newspaper. "It's disappeared little by little, and now I suppose it might die with me."
Although it survived the Spanish conquest, Ayapeneco is believed to have gradually disappeared as a result of compulsory Spanish education, migration of its speakers and urbanisation.
Segovia, who denies any active animosity with Velazquez, spoke Ayapaneco with his brother until he died about a decade ago. Segovia still uses it with his son and wife who understand him, but cannot speak more than a few words themselves.
Velazquez reputedly does not regularly talk to anybody in his native tongue anymore.