The misuse and misunderstanding of adverbs by nonnative speakers of English are examined, and the approaches of commonly-used grammar texts to these problems are discussed. Two separate studies provide information for examining adverb use: a longitudinal study of the written work of 23 adult students in two low-to-intermediate level intensive classes of English as a second language (ESL), and a cross-sectional study of 22 of 123 students taking a placement examination for an ESL program. Three categories of adverb errors were studied: misplacement, confusion with other form classes (e.g., adjectives), and inappropriate usage. Results of the studies and a comparison of four major approaches to teaching adverb usage indicate that the most common adverb error, confusion between adverbs and other syntactic constituents, receives the most attention in textbooks and also seems to increase in incidence as proficiency increases. It is suggested that current methods for teaching adverbs need to be either substantially revised or redoubled at an early stage of instruction, because they appear to be encouraging errors. (MSE)