BASQUE

Set to 2 different clues across 2 published puzzles, most often “Language with no known relative” — The New York Times, Thursday, 24 August 2000.

6 letters

Every clue on record, most used first

Language with no known relativeonce
The New York Times — Thursday, 24 August 2000
Native of northern Spainonce
The New York Times — Tuesday, 4 June 1996