The overarching dialectic treated in this work is framed in terms of the familiar ‘synchronic-diachronic’ opposition indicative of 20th century linguistic dualism. Taken as a strict dichotomy, synchrony and diachrony are, ipso facto, irreconcilable. If we distance ourselves from the old essentialist presuppositions and approach the actual unfolding of language use and linguistic cognition in time and space with more probing, phenomenological attitudes, the distinction itself becomes liable to an ontological-conceptual shift. Instead of generating artificial binary choices (e.g., between past vs. present, history vs. typology, reconstruction vs. description), synchrony and diachrony emerge as profoundly involved in each other’s affairs in limitless combinations of underlying complementary tensions – tensions that might be more aptly re-framed in interdependent biological terms (see dialogue between Croft 2010 and Mufwane 2010 for precedence and potential problems). In place of the ‘synchronic-diachronic’ dyad, a biology-oriented triad suggests itself, including ‘ecological’, ‘phylogenetic’ and ‘ontogenetic’ contingencies: linguistic ecology including both synchronic context and diachronic contact; linguistic phylogeny including both diachronic lineage and synchronic inheritance; and linguistic ontogeny mediating between the two in the form of specific, polylectal speech varieties growing through space and time. … Attempting to choose between the two seems, at best, more and more shortsighted.

—Jamin Pelkey (2011), Dialectology As Dialectic: Interpreting Phula Variation, viii.

In short: the synchronic-diachronic distinction is highly artificial.Now, we might see appeals to Saussure’s chess analogy: you don’t need to know the history of a chess board to evaluate the current state of play. And this is true. The entire premise of studying chess problems is built up on that premise: respond and evaluate to the current state of play. But it misses a larger point: Saussure, in using chess, explicit highlights a game where past events regularly, predictably, and inevitably determine the present resulting state (Sweetser 1990:10). And indeed, research into the nature of human expertise, broadly, demonstrates that even learning and working on chess problems depend on larger issues of pattern matching built up over time, as illustrated in in the Veritasium video below:

Learning anything, whether chess or language, is always a blend of the synchronic and the diachronic together. The patterns that master chess players develop come with time, practice, and immediate feedback. The patterns in language, as we speak it, are the same. Our synchronic experience of language is built upon our own diachronic experience of pattern matching. And those patterns form the basis and pathways of language change through the generations.