There is an abundance of work on heritage speakers’ use of morphology, and this chapter has made an attempt to summarize the results by tracing general patterns within the embarrassment of empirical riches. Heritage speakers produce a great number of errors in morphology, but only some of those errors reflect fundamental shifts in their own grammar. Most of the problems can be attributed to online limitations, which somewhat resemble the issues found among other vulnerable populations—including child language learners and L2 learners. Morphological errors in heritage production are rarely due to transfer from the dominant language. The chapter identifiesd instances of overmarking and overgeneralization in heritage grammars, many of which are mostly found in production. Perceptually salient elements are better maintained and more readily noticed; they may also replace forms that are perceptually less salient. This generalization can help us make predictions about the fate of certain elements in a given heritage language. If there is a paradigmatic contrast between two elements in the language, then the perceptually salient element is likely to be retained.