Table 3.
Means and standard deviations for age 5 MLU and IPSyn scores by group.
| Two-group analysis | TD (n = 20) | LT (n = 34) | |
|---|---|---|---|
| MLU | 4.41 (0.62) | 4.04 (0.56) | |
| IPSyn total score** | 48.25 (8.49) | 41.00 (8.21) | |
| IPSyn noun phrase | 7.72 (1.53) | 6.97 (1.38) | |
| IPSyn verb phrase | 17.61 (2.95) | 16.42 (3.79) | |
| IPSyn question/negation* | 7.94 (3.37) | 6.00 (2.48) | |
| IPSyn sentence structure* | 14.83 (4.82) | 11.64 (4.17) | |
| Three-group analysis | TD (n = 20) | LB (n = 24) | CLT (n = 10) |
| MLU*** | 4.41 (0.62) | 4.32 (0.36) | 3.37 (0.37) |
| IPSyn total score*** | 48.25 (8.49) | 43.61 (7.36) | 35.00 (7.04) |
| IPSyn noun phrase | 7.72 (1.53) | 7.13 (1.52) | 6.60 (.97) |
| IPSyn verb phrase* | 17.61 (2.95) | 17.13 (3.22) | 14.80 (4.54) |
| IPSyn question/negation | 7.94 (3.37) | 6.26 (2.38) | 5.40 (2.71) |
| IPSyn sentence structure*** | 14.83 (4.82) | 13.13 (3.44) | 8.20 (3.77) |
Note. MLU = mean length of utterance (Brown, 1973); IPSyn = Index of Productive Syntax (Scarborough, 1990); TD = typically developing; LT = late talker; LB = late bloomer; CLT = continuous late talker. Late bloomers were defined by an MLU score within 1 SD of the TD group mean, using the TD group SD.
*
p < .05.
**
p < .01.
***
p < .001.