Table 4.

Published studies of vowel formant frequencies for children of different ages (in years). The values in the cells are the numbers of participants studied at each age or age group. All studies are of children presumably learning American English as their first language. A – Robb & Cacace (1995); B – Kuhl & Meltzoff (1996); C – Kent & Murray (1982); D – Robb, Chen, & Gilbert (1997); E – Bickley (1989); F – Gilbert, Robb, & Chen (1997); G – McGowan, Denny, & Nittrouer (2014); H – Chung et al. (2012); I – Yildirim, Narayanan, Byrd, & Khurana (2003); J – Eguchi & Hirsh (1969); K – Perry, Ohde, & Ashmead (2001); L – Kohn & Farrington (in press); M – Assmann, Nedarey, & Bharadwaj (2008); N – S. Lee, Potamianos, & Narayanan (1999); O – Bennett (1981); P – Jacewicz, Fox, & Salmons (2011); Q – Hillenbrand et al. (1999); R – Angelocci, Kopp, & Holbrook (1964). 83

Age/ Study	<1	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18
																				A	20
B	72
C	21
D	20	–	–
E	40	–	–	–
F		4	–	–
G		6	6	6	6
H			10			10
I				12	–	–	–
J				5	5	5	5	5	5	5	5	10	10	10
K					20				20				20				20
L					10						20				20		20
M						10	10	10	10	10	10	10	10	10	10	10	10	10	10
N						32	27	35	36	48	39	43	43	39	21	22	22	19	20
O								42	–
P									94	–	–	–	–
Q											46	–	–
R												18	–	–	–