This paper discusses how to verify hypotheses about the use of a given lexical choice when synonymic pairs of archaisms and preslavisms (and their different readings) occur in manuscripts of both direct and indirect traditions of the Didactic Gospel [DG] of Constantine of Preslav. Using three synonymous pairs as examples (тъкъмо/тъѭ, постт/алъкат, пастꙑрь/ пастѹхъ), the paper illustrates the potential of lexicological and textual analysis (identifying the frequency and distribution of synonymic pairs in the text, examining their semantic differences, and analyzing the different readings in textual transmission). The work highlights how the existence of synonymic pairs often influences a priori assumptions in discussions concerning the unique characteristics of the homiletic collection, leading to the identification of geographical and temporal markers of the Preslav redaction in the text. Finally, the work shows that Constantine of Preslav’s Didactic Gospel reflects the transitional nature of late 9th century Bulgaria, marked by the Christianization of Slavic communities – a period and a text where written and spoken language, the language used in liturgical, homiletical, and intra-church communication coexist, despite their different norms.