This attribute encodes information concerning the choice of auxiliary for perfect or compound tenses and obviously is language-specific (e.g. `have', `be' for English).
This is used in Dutch for verbs including separable particles, such as
This Boolean-valued feature is introduced at language-specific level to encode the presence in the verbal form of the clitic.
The values proposed here for English are ing-form and base-form. The value infinitive incorporating `zu' is added for German.