The four distinct groups of teachers (mainstream, ESL, bilingual, and foreign language teachers) responsible for instruction in English as a second language (ESL) to limited-English-speaking children are compared in terms of the standards set for each in teacher training curricula and the common topics of research in each of the four fields. It is concluded that overlaps in teacher preparation requirements, commonalities in discipline-specific standards, and similarities in training for dealing with like groups of students imply that differentiated teacher grouping helps to intensify the focus and specificity of training, and that attention to common needs and preparation makes the process of organizing, designing, and implementing inservice training activities more effective. It is also suggested that a commonality of research topics in the four areas provides a cohesive framework from which to develop training. (MSE)