Aspects of the Morphophonology of the Verb in Latin and in German and English

As shown by the 1st person plural examples in (1a), the present tense forms consist of a Verb Stem followed by a Theme vowel and end with the 1st person plural Agr(eement) morpheme /-mus/. In the contrasting 1st person singular forms, shown in (1b), although the Theme vowel appears in /de:l-e-o:, aud-i-o:, cap-i-o:/, it does not appear in /port-o:, leg-o:/. How does one formally account for this difference? In traditional treatments of Latin grammar—for example, the summary of Latin grammar appended to The Pocket Oxford Latin Dictionary (Oxford University Press 1994) or to be found in Barron’s Latin Grammar (Maidhoff 2009)—the verbs are assigned to the same classes as in