Four major areas of research into verbal development are discussed: (1) the relationships between behaviors hypothesized to be associated with one of the four major language skills, (2) the sequencing or ordering of behaviors within a skill, (3) the relationships between behaviors associated with different skills, and (4) the relationships between knowledge or understanding of language properties and verbal performance. The basic strategy for research on verbal development is dependent on a scheme which contains the following important elements: (1) a mapping of the entire verbal domain, so that results of researches in particular segments can be related to each other, (2) the use of the same scheme across investigators and situations where appropriate, to maximize understanding both of the phenomena under consideration and of the investigators by each other, and (3) the development of reliable and longitudinal measures specific to the elements of the scheme. Verbal measures for use with children from three and one-half years of age to age eight-nine (Grade 3) are presented in a table, and verbal skills, receptive and productive, are also tabulated. (DB)