Attaining competence in a language is very important to the speakers of any language, and more so to those who learn a language for a particular purpose. However, it is not always easy to attain competence due to the influence of the learners'' first language. This book explores the syntactic errors, which result from L1 transfer in the process of acquiring English as a second language by Keiyo L1 learners of English, and whether teaching plays a role in the elimination of the errors. Error analysis and Inter-language theories constituted the theoretical framework of the study. The study sample was drawn from pupils who are L1 speakers of Keiyo. This book is a major scholarly contribution in Second Language Acquisition studies and language education curriculum planning.