“…A number of acoustic and perceptual studies of Vietnamese tones have been conducted since the 1960s [Trần, 1967;Han, 1969;Han and Kim, 1974;Earle, 1975;Gsell, 1980;Vũ, 1981Vũ, , 1982Seitz, 1986;Đỗ et al, 1998;Phạm, 2001;Brunelle, 2003;Phạm, 2003;Honda, 2006;Ingram and Nguyễn, 2006;Brunelle and Jannedy, 2007;Brunelle, 2009c, b;Kirby, 2010]. However, their production has not been investigated as exhaustively as their acoustics and perception, despite a few solid articulatory studies [Nguyễn and Edmondson, 1997;Michaud, 2004a;Vũ et al, 2005;Michaud et al, 2006;Nguyễn et al, 2009].…”