Figure 9.

F3–F2 differences for vowel /ɝ/ as a function of speaker age in males and females. Data sources for males are as follows: dashed line = 11- to 14-year-olds in Angelocci et al. (1964); cross = Childers and Wu (1991); unfilled circle = Hagiwara (1995); solid line = 10- to 12-year-olds in Hillenbrand et al. (1995); unfilled squares = Lee et al. (1999); unfilled diamond = Peterson and Barney (1952); filled circle = B. Yang (1996); filled diamond = Zahorian and Jagharghi (1993). Data sources for females are as follows: filled diamond = Childers and Wu (1991); inverted triangle = Hagiwara (1995); solid line with filled circle = 10- to 12-year-olds in Hillenbrand et al. (1995); filled circle = adults in Hillenbrand et al. (1995); unfilled circles = Lee et al. (1999); filled triangle = Peterson and Barney (1952); unfilled diamond = B. Yang (1996); unfilled diamond = Zahorian and Jagharghi (1993).