Unmarked/uninflected infinitives

[Rudolph C Troike]

The distinction of marked vs unmarked infinitives comes from the
historical basis that, as in modern German, the verb form following a
modal is inflected with the infinitive suffix (-en in German, -an in Old
English). The preposition "to" occurring before what was a dative-marked
infinitive came to be perceived as the inflectional equivalent of the
infinitive itself as the original suffix (actually double-suffix) was
dropped (perhaps much as "pas" in French has come to be perceived as the
negative element, with the original "ne" fading). So although it is
historically odd to call "to" the "inflection" for the infinitive, it is
functionally that, while the historically equally inflected infinitive
after modals, now the "zero" form in Chomskyan TG terms, is now the
uninflected infinitive form. All zeros are not equal.
        --Rudy