Cooke, Joseph R.Cooke, J.2021-12-012021-12-01858833867PL-A80.159http://hdl.handle.net/1885/253597application/pdf© 1989 Joseph R. Cookehttp://creativecommons.org/licenses/by-sa/4.0The problem of the sixth tone in Thai198910.15144/PL-A80.159 2021-12-01Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)