In certain Germanic languages, there is a group of verbs called preterite-present verbs that are often viewed as irregular, but in fact behave very predictably. They exhibit a morphological phenomenon called deponency, often in conjunction with another morphological phenomenon called heteroclisis. I examine the preterite-present verbs of three different languages: Old Norse, Modern Icelandic, and Modern German. Initially, I approach them from a historical perspective and then seek to reconcile their morphology with the modern perspective. A criteria is established for a canonical preterite-present verb, and then using a lexical programming language called DATR, I create code that generates the appropriate paradigms while also illustrating the morphological relationships between verb tenses and inflection classes, among other things. DATR is a programming language used specifically for language models.