Objective: The purpose of this study is to investigate the use of modeling during routine-based activities with an increased intensity of sessions on verbal communication attempts and expressive vocabulary. Method: Three participants 24-37 months of age were recruited for this A-B-A-B single-subject design. Treatment sessions took place 5 times a week for 30 minutes per sessions in the home during routine-based activities (two sessions were held at the local park). The dependent variable was the number of new vocabulary words produced during a 30-minute session. The criterion level for acquisition was set at 10 different and new vocabulary words. The independent variable was the use of modeling (recasting, self-talk, parallel talk, and focused stimulation) during routine-based activities. Results: All three participants increased their expressive vocabulary. P1 increased his vocabulary by learning 147 new words, P2 by learning 115 new words, and P3 by learning 157 new words. This positive growth in vocabulary for all participants revealed a possible functional relationship between the intervention and the dependent variable. Conclusion: The use of modeling during routine-based activities at a high frequency over a short period of time yielded positive results for all three participants. There was a positive, accelerating trend during the intervention phases. While the withdrawal phase revealed continued learning for each participant, the level of growth between participants was not as varied or to the same degree as seen during the intervention phase.
