The given article dwells on the role of Academician Shakhmatov‟s linguistic legacy in the development of classical and non-classical linguistics in the spheres of philological researches. Alexei Shakhmatov „s linguistic concept allowed to make significant improvements in the description of syntactic units of the language tiers; the study of the parts of speech, the grammatical category of language. The article also dwells on Shakhmatov‟s discoveries in the methodology and techniques of linguistic researches. A special attention is drawn to the interpretation of the dichotomy of "synchron" / "diachronic" in the study of sound system of the old Russian language. The given article focuses on Shakhmatov‟s lexicographical activities