The present study examined the influence of Singapore Colloquial English (SCE) on Standard English word spelling through a plural formation task of four words ("man", "tooth", "dress" and "child") among 168 Singaporean bilingual children with Chinese background. It was found that "dropping the plural" was the most prevalent type of error. Poor readers made more random errors, and good readers made more overgeneralization errors and formed more correct plural forms. Similar error patterns held for spelling achievement groups, except that good spellers also made more dropping plural errors than average spellers and poor spellers. The results of this study point to the importance of considering oral language influences on children's development of morphological knowledge. The presence/absence of various morphological features in the spoken language may predict the relative difficulty of acquiring certain morphological rules for the standard written variety. (Contains 4 tables and 3 figures.)