Figure 9.

Noun types (top panel) and tokens (bottom panel) in infants’ input by age, talk status (i.e., whether or not the infant has said their first word), and gender. Each point represents one participant’s word count each month. Y-axis (and regressions) used square root-transformed noun counts due to skewness. Squares and solid lines indicate infants not yet talking; triangles and dashed lines indicate infants who have begun talking. Shaded bands indicate 95% confidence intervals. For both types and tokens, we find a main effect of age, a talk status-by-gender interaction, and a talk status-by-age interaction, but not a 3-way interaction (see text for details).