The article is devoted to the study of imitative (iconic, onomatopoeic, sound symbolic) words from the diachronic perspective. The main questions discussed are the number of imitated words in the lexicon and their age. The material for the study includes 1500 Modern English and 300 Old English onomatopoeic and sound symbolic words selected by continuous sampling from relevant etymological dictionaries. Examples are drawn from other languages of the Indo-European family-Gothic, Old Norse, Icelandic, German, Russian and other. The main conclusion of the article is that imitative words existing in modern languages are not likely to be old coinages, which suggests that the historical-comparative reconstruction of onomatopoeic and sound symbolic roots should be conducted with great caution.