The ancestors of our modern auxiliaries before the Modern English period certainly had more verblike properties than their modern descendants, as we saw in Chapter 4. And most of the formal differences which distinguish so sharply between modern auxiliaries and full verbs had not then developed. But it is too simple to conclude that they were therefore verbs four square in all essential syntactic properties with other verbs at this period, with (say) Lightfoot (1979), for they already share striking characteristics which apparently isolate them. This chapter will be taken up with the establishment and discussion of two of the most striking of these characteristics, their behaviour in ellipsis and with impersonals. These are important because they hold at the level of sentential syntax and they look on the face of it like potential wordclass properties. The conclusion which will seem most plausible for Old (and Middle) English is that there was already a formal subcategorial distinction within the class of verbs. In the next chapter this position will be reinforced, and Chapter 7 will discuss the notional identity of this grouping.

At the end of Chapter 4 three questions were isolated as methodologically central in determining word-class status. The first two were:

1. (i) Do these words have formal properties which distinguish them from other verbs?

2. (ii) If so, do such formal properties typically cooccur with each other, so that there is a measure of predictability between properties which might characterize a distinct group?