Background: Very little research has investigated the use of the information carrying words (ICW) construct within language interventions, despite its very widespread use in speech and language therapy in the United Kingdom. The Language Enrichment Activity Programme (LEAP) is an intervention programme that applies the ICW construct to differentiate children's level of need and structure play-based learning activities. LEAP sessions are designed to be child-led, building language skills through application of communication supporting strategies (CSS) such as modelling, recasting and inviting communicative participation via choices and expectant pausing. Aims: This study aims to evaluate the impact of trainee speech and language therapists (SLTs) delivering LEAP on the language skills of primary school children (aged 4-6 years). Methods and Procedures: One hundred eighteen children were selected by their teachers. Participating children were semi-randomly allocated to either a control group (n = 48) or to a group that received 12 sessions of LEAP over 6 weeks (n = 70). A smaller sub-cohort was followed up 8 weeks following the end of LEAP (received LEAP n = 41, control group n = 46). LEAP was delivered by trainee SLTs to small groups of children. Assessments were carried out blind to group allocation pre- and post-intervention in order to evaluate the impact of intervention on receptive and expressive language skills. Outcome measures were a bespoke comprehension and expression outcome measure and the Renfrew Action Picture Test (RAPT; Renfrew 2019). Results: Children who received LEAP had improved scores on both the RAPT assessment and the bespoke outcome measure. There was a significant interaction between time (pre- and post-intervention) and group (those who received LEAP vs. the control) for the RAPT grammar score, and the LEAP vocabulary and expressive ICW score. LEAP had less of an impact for a sub-cohort followed up 8 weeks following the intervention, with only the LEAP expressive score showing significant interaction between the three assessment time points and group (those who received LEAP vs. the control). Conclusions and Implications: The LEAP was successfully delivered to small groups of children and supported them in developing their expressive language skills. Working with trainee SLTs increased the capacity to deliver LEAP at a low cost to schools. Results are promising and add to an emerging evidence base for the application of the ICW construct within SLT intervention programmes.