Figure S8 10°F found _| 5 finded 10 yO 10° al yr YY 10° dwelt s dwelled 10 i eae ry 5 10? even ley 2 Feo 0 Lamu 410 = Spilled 210° fe | > oe 410° ERS SBiled 210° eee a 1800 1850 1900 1950 2000 Year Fig. S8. Example of grammatical change. Irregular verbs are used as a model of grammatical evolution. For each verb, we plot the usage frequency of its irregular form in red (for instance, ‘found’), and the usage frequency of its regular past-tense form in blue (for instance, ‘finded’). Virtually all irregular verbs are found from time to time used in a regular form, but those used more often tend to be used in a regular way more rarely. This is illustrated in the top two rows with the frequently-used verb “find” and the less often encountered “dwell”. In the third row, the trajectory of “thrive” is one of many ways by which regularization occurs. The bottom two panels shows that the regularization of “spill” happened earlier in the US than in the UK. HOUSE_OVERSIGHT_017047