Abstract

This paper deals with the historical development of two auxiliaries, modals and the aspectual auxiliary have. In Present-day English, their syntactic behaviors are different: (1) Modals take bare infinitives as their complements, whereas havee takes a past participle. (2) Modals must precede have, but have cannot precede modals. In Old and Middle English, they both could take NP complements just as main verbs did.
This paper historically examines why these differences emerged. In the first place, modals and have were grammaticalized as auxiliaries in a certain period, but the processes of their grammaticalization were not the same. Secondly, as for the assignment of θ-roles, which is a major factor that distinguishes verbs from auxiliaries, modals and have cannot θ-mark as a result of their grammaticalization. Thirdly, however, have still retains the ability to assign Case to INFL in their complements, though modals cannot assign Case. Fourthly, modals and have were classified as functional and lexical auxiliaries, respectively.
Furthermore, I will show the validity of our analysis by applying it to German. German modals and aspectual haben ‘have’ are lexical auxiliaries and both can assign Case to INFL. As a result, both word orders “modal+haben” and “haben+modal” are possible in German.