This professional development (PD) study examined the effect of feedback type on changing preschool teachers' use of language enhancement strategies and language outcomes for children. We included 21 Head Start teachers and 107 children. We randomized classrooms to PD feedback condition: (a) self-reported or (b) observed use of strategies. All teachers completed online learning modules on language enhancement strategies (i.e. open-ended questions, self-talk, repetition, expansion, and narration) and teacher self-monitoring. After completing the PD, teachers were provided weekly, individualized feedback based on their submissions of: (a) self-reported, or (b) observed performance (via 10-min video) of their use of language enhancement strategies. Results suggested that the PD experience (less than 8 weeks, 1 h per week) increased teachers' frequency in using language enhancement strategies (performance, Hedges' g = 0.65; self-report, Hedges' g = 1.43) across condition, with no significant differences by condition. Additionally, children demonstrated mean gains in expressive vocabulary and overall language skills. We believe that this brief, but targeted PD experience, warrants further research to explore the impact of using self-reported feedback with a larger sample. Determining more efficient and effective PD approaches will enable the field to better meet the needs of teachers and improve outcomes for children.