TAHLEQUAH, Okla. (AP) — One of the last members of the Cherokee Nation who spoke and understood only the Cherokee language has died at 88.

Mack Vann’s nephew, Gary Vann, says his uncle died of pneumonia Monday in a hospital in Tahlequah, Oklahoma, while undergoing treatment for an ongoing heart condition.

Mack Vann would greet people with the word “osiyo,” the Cherokee word for “hello.” He was a descendant of Andrew Ross, brother of Cherokee Chief John Ross, who led the tribe from its ancestral home in Georgia to Oklahoma during the forced relocation known as the “Trail of Tears.”

He told The Associated Press in 2014 that he learned some English in school but quit after fourth grade to help with the family farm and slowly forgot how to speak it.