This study is concerned with linguistic obstacles in the production, transmission, and dissemination of scientific and technical information at the international level. Special reference is made to the problems of developing nations. Following brief discussions of the early use of language, the beginning of diversity of languages, diversity of languages in science and technology, and concerns at the international level, the paper is divided into five major sections. The first provides basic data on the language distribution of the scientific and technical literature, including the approximate numbers of scientific works published each year in the major languages and the language distribution of items in major abstracting/indexing periodicals. Use patterns are examined in the second section through analyses of such areas as the percentages of the literature read in English by research workers in different language areas and amount of borrowing from the library in various disciplines and languages. The third section discusses the foreign language problem in English language countries in the context of the linguistic abilities of the researchers, the amount of research in various scientific disciplines done in different countries, and steps that have been taken to overcome the language barrier for French, German, Russian, and Japanese. The point of view of developing countries is addressed in the fourth section, which includes a detailed case study of the scientific language situation in India. The fifth section explores ways in which researchers cope with language barriers, and suggests sources where they may find help, ranging from colleagues to translation services. Fourteen recommendations designed to ease language barrier problems conclude the report. A 78-item bibliography is included. (THC)