There are more than 7,000 languages currently spoken in the world but many aren't recorded and don't have a written form.
Unesco warns that by the end of this century, more than half of these are likely to disappear.
One of those dying languages is Wichita - a native American tongue.
Doris McLemore, 83, is the last fluent speaker of Wichita.
Al-Jazeera's Rob Reynolds travelled to Taah-leqwah in Oklahoma to meet her.
[14 May 2010]