Table 3 Assessment Results of Children’s Verbal Behavior Development

Participant Chronological Age (Years) Milestone Level(Months) Overall Level (Months)
Motor Imitation Vocal Imitation Listener Response Intraverbal
A 6.8 1-M 0-M 2-M 0-M Level 1 (0-18)
B 6.2 10-M 10-M 10-M 9-M Level 2 (18-30)
C 4.3 10-M 10-M 10-M 10-M Level 2 (18-30)
Notes. M (Milestone) indicates the number of developmental milestones reached in each verbal behavior domain according to the VB-MAPP Milestones Assessment. The VB-MAPP divides milestones into three levels based on typical developmental age: Level 1 (1-5M, 0-18 months); Level 2 (6-10M, 18-30 months); Level 3 (11-15M, 30-48 months).