The results are presented here of an investigation into the development of receptive and expressive English grammar when this is acquired as a second language. A cross-sectional survey using standardised assessments was conducted. 103 children were randomly selected from three local primary schools. These children were aged between 5 and 11 years and were acquiring English sequentially. Data relating to the receptive and expressive grammar of English as a second language was collected from each child. Analysis of this data revealed preliminary developmental patterns that appear to be specific to the sequential acquisition of English grammar. This data confirms the importance of not using data pertaining to the acquisition of first language English for English that is acquired as a second language.