AbstractThe present paper deals with a marginal divergent spelling consisting in the geminatio of a consonant littera in pre- or post-consonantal position. The phenomenon is found in both Latin and Greek non-literary texts. The analysis is conducted on two levels, one grapho-phonological and one historical. In fact, the phenomenon results to be particularly relevant as for the relation between spelling and syllabic representation of heterosyllabic clusters and as for the dimension of contact between Latin and Greek scripts. First, a synchronic cut of Latin non-literary texts is examined to evaluate the occurrence of this geminatio and its ratio of distribution along the different types of clusters. It can be stated that the geminatio at hand represents a metagraphic signal of syllab(ific)ation indeterminacy, as is further corroborated by the examination of metalinguistic sources. Secondly, the historical perspective is then addressed. This spelling can be interpreted as a feature, albeit marginal and stemming from ephemeral slips, of writing koine, as is further evidenced by the examination of two sample clusters of texts.