Of, pertaining to or concerned with changes that occur over time.
2012, Paolo Ramat, Sturtevant's paradox revisited, Thomas Stolz, Hitomi Otsuka, Aina Urdze, Johan van der Auwera (editors), Irregularity in Morphology (and Beyond), [page 61],
Consequently, the perspective will be more diachronic than synchronic.