General developments for the combined auxiliary class

The analyses to be described here treat growth spurts in auxiliary frequency as suggesting developments in the child's rule system. Frequency is considered from three different perspectives: auxiliary tokens and auxiliary types per 100 structured utterances, and the rate of inclusion of certain forms in obligatory contexts.

Figures 5.1, 5.2, and 5.3 plot the frequency, range, and cumulative range of auxiliary forms over successive recordings. By comparing curves for frequency and range it is possible to develop hypotheses about distinctive styles of learning during those periods when the two do not develop in parallel.

Frequency of auxiliaries

The maximum frequency ranges from 16 (Daisy) to 38 (Betty) auxiliaries/100 structured utterances. To put such figures into perspective, an estimate for adult-adult conversation was obtained using the Bristol corpus. Eight transcripts of the younger Bristol children at 1;3 were taken at random and analysed for number of auxiliaries/100 structured adult-adult utterances. The mean value obtained was 50.8, well above the maximum figure for the Welsh children.

Figure 5.1 shows that while there is a clear increase in frequency over time, development is usually not linear, though Clare and Eric's progress is less marked by regressions than the remaining children. It is also difficult to identify single points at which there are sharp increases in the steepness of curves which might be indicative of changes in rule systems. However, six children show fairly rapid increases at some stage, the exception being Daisy whose maximum of 16.0 auxiliaries/100 structured utterances is considerably lower than for other children.