The article discusses the principle of extracortical organization of higher psychological functions and its significance for the development of modern neuropsychology. The role of outside factors (stimuli, signs) in establishing functional links between different brain systems is in principle universal. But in different cultures different tools (means) are developed. The existing means also differ significantly (direction of writing, orientation by means of maps or behaviour of sea birds etc.). Therefore neuropsychological analysis of higher psychological functions requires taking into ac-count cross-cultural differences. It is also essential that diagnostic instruments be adjusted to different cultural contexts. The author illustrates effectiveness of the above principle in analyzing brain organization of speech in the process of learning to read and write and in acquiring a new language.