Children who are deaf or hard of hearing (DHH) in Sri Lanka have inadequate access to early amplification and language stimulation. As a result, they are at risk of impoverished language development: spoken language and sign language. Thirty DHH children who use Sri Lankan sign language between the ages of 4;4-7;2 years from three classrooms of a School for the Deaf were included in this study. The culturally-modified "Box Clever" language-enrichment programme was offered as a whole-class approach twice a week during a 12-week school term through the class teacher. Pre- and post-intervention language measures and statistical analyses of language scores were undertaken of receptive and expressive vocabulary on picture-naming tasks of target vocabulary. In addition, content and syntactic analyses of narrative skills were undertaken using the "Elephant Tales Narrative Assessment," an informal assessment created by the researchers, as no local formal standardised assessments exist currently. There were promising results with statistically significant positive gains in receptive and expressive vocabulary skills on target vocabulary items post-intervention by all the participants. Positive qualitative differences were observed in the content within the target narrative assessment post-intervention by all participants with evidence of the emergence of two to three sign combinations by many of the children.