In Jamaica, from grade 1 up, patterns of the Standard Jamaican English (SJE) sound system are taught in classes with a view to helping children become conscious of the different shapes of sounds. The aim of this article is to examine one of those patterns: the pronunciation of (-t, -d) consonants in word-final consonant clusters in words such as must, went, accident, cold, left. Twenty-four children-seven years of age and one teacher were studied. It is widely known that most children in Jamaica learn SJE as a second language, principally via schooling, and that the use of vernacular features is still discouraged inside the classroom, especially when addressing the teacher. The primary language of the children, i.e. the one acquired at home, is Jamaican Creole (JC). This article seeks to show the level at which children discriminate between JC clusters and SJE clusters, first in their actual production, and second, in their mental representations of the systems.