The article deals with the notion of the genetic code and its metaphorical understanding as a “language”. In the traditional view of the language metaphor of the genetic code, combinations of nucleotides are signs of amino acids. Similarly, words combined from letters represent certain meanings. The language metaphor of the genetic code, 171–200, 2011) assumes that the nucleotides stay in the analogy to letters, triples to words and genes to sentences. We propose an application of mathematical linguistic methods on the (...) notion of the genetic code. We provide quantitative analysis of mRNA strings and natural language texts. This analysis is sensitive to the detection of the code units hierarchy. We also take into consideration a representative quantitative analysis of DNA, RNA and proteins. Our analysis of mRNA confirms an assumption that the design of the genetic code cannot analogize DNA bases and letters. The notion of the letter is much more appropriate if analogized with triplets or amino acids, 187–191, 2017). (shrink)