How fine are parallel principles governing morphology and syntax? On the hunt for explanations of morpheme orders

There are now a variety of models available for describing morphology. Some are more static, simply laying out structure, while others are more dynamic, proposing sequences of operations by which structures might be derived. Different models might be useful for different purposes, different constructions, and different languages. But we can go beyond description toward explanation of the structures that exist by incorporating the diachronic dimension, examining the kinds of processes by which morphological structures develop over time in individual languages, then extracting general principles. Much of what we find synchronically might seem unmotivated until it is recognized that morphology reflects the crystallization of sequences of individual developments, each motivated at an earlier point in time. Such an approach is illustrated here with the development of tense morphology in languages of the Iroquoian family, indigenous to eastern North America.