Table 2.
Mean and SD for percent vowels correct for typically developing boys and girls.
| Vowel | Sex | 4- to 5-year-olds: percent correct mean (SD) | Sex | 6- to 7-year-olds: percent correct mean (SD) |
|---|---|---|---|---|
| /i/ | F | 100 (0) | F | 100 (0) |
| M | 100 (0) | M | 100 (0) | |
| /u/ | F | 99 (2) | F | 99 (2) |
| M | 98 (4) | M | 98 (5) | |
| /æ/ | F | 97 (5) | F | 98 (5) |
| M | 98 (4) | M | 98 (4) | |
| /ɑ/ | F | 89 (10)* | F | 97 (5) |
| M | 95 (7) | M | 98 (3) |
Note. The only speaker group with a mean of less than 95% and a standard deviation greater than 7% is marked with an asterisk (*). F = female; M = male.