Abstract
Romance verb stem alternations (e.g., Spanish tengo `I have' vs. tienes `you have') constitute seemingly unnecessary but highly inheritable morphological traits. Using novel phylogenetic methods, we assess the impact of frequency and alternation patterns on properties of their evolution, specifically on the speed of change and the long term preference for pattern types within lemmata. We find credible differences in long-term trends between alternation patterns, and confirm the notion that frequency drives the maintenance of irregular patterns. However, our model reveals no or only weak effects of either predictor on the speed of change. Our findings call for modeling the multiple dimensions of language change jointly but with distinct parameters for speed (or rates) of change and long-term preferences.