Introduction

Tags can combine Negation, Inversion and Code (ellipsis), three of the defining characteristics of the auxiliary, and it was suggested in Section 2.2.3 that evidence of a range of auxiliaries in tag questions, particularly if they reverse the polarity of an auxiliary in the matrix clause, could be used as a criterion of acquisition. However, we have seen in Chapter 6 that two children (Alex and Clare) use auxiliary forms in tags before their recorded emergence in less complex contexts. On the other hand, another child (Gemma), who by the end of the study has shown the most evidence of rapid advances in auxiliary verb learning, produced no tags at any stage.

The possibility that apparent contraventions of the Complexity Principle are the result of sampling error was mooted above. Initially, therefore, this chapter addresses the issue of whether the first occurrence of tags for Clare and Alex is genuinely early in relation to other aspects of their development, and whether the features of these tags support the interpretation that they are produced as unanalysed wholes. Secondly, the non-occurrence of tag questions for Gemma will be related to general syntactic and auxiliary verb development to discover whether she has sufficient mastery of the separate grammatical processes involved in tag production to make their emergence possible. Two other preconditions for tag production will also be considered: the availability of tags in the speech addressed to her, and her ability to process utterances of comparable length and complexity.