The article presents the results of research on visual recognition of Russian sound-imitative (SI) words by native speakers (N = 106) in a lexical decision task. Each subject was presented with 64 non-words and 64 target stimuli (a total of 128 stimuli). The target stimuli were equally represented by neutral (non-SI) words and SI words (32 words each). SI words were divided into 4 groups (8 words per group) according to the principle of reducing the degree of iconicity, understood as the loss of sound imitative properties in the process of language evolution, so that the most iconic (explicit) SI words were assigned to group 1, and completely de-iconized SI words were assigned to group 4. The target stimuli were monosyllabic low-frequency words (from 0.4 imp to 18.3 imp, M = 5.3 imp). The results revealed speed and accuracy rates of SI words recognition depending on their de-iconization stage (loss of iconicity). The findings show that explicit SI words were recognized most slowly and with the largest number of errors. We assume that this can be attributed to the fact that they belong to the class of immutable words. De-iconized words, however, having all the characteristics of notional parts of speech, were recognized faster than non-SI words. We suggest that the interaction of SI and the part of speech of a visually perceived word affects the process of cognitive processing. It is noteworthy that recognition of non-integrated imitative words requires more cognitive resources than recognition of words fully integrated into the language system.