Interactions Among Morphology, Word Order, and Syntactic Directionality: Evidence from 55 Languages

This study investigates interactions among morphology, word order, and syntactic directionality across 55 languages from 11 families. We quantify morphological richness (moving-average mean size of paradigm), word order flexibility (entropy), and syntactic directionality (dependency direction), linking linguistic structure to information-theoretic principles. Analyses show that morphological richness is only weakly related to word order entropy and does not provide a robust predictor after statistical correction. Rich morphology facilitates the predictability of syntactic functions. Languages with richer morphology consistently favor head-final structures, whereas minimally inflected languages lean toward head-initial patterns, indicating that syntactic directionality is more closely associated with morphological complexity than with surface word order. Overall, the findings indicate that languages maintain a balance between redundancy and flexibility in optimizing information transmission, providing quantitative evidence for efficiency-driven trade-offs in human language.