  The English language has evolved dramatically throughout its lifespan, to the
extent that a modern speaker of Old English would be incomprehensible without
translation. One concrete indicator of this process is the movement from
irregular to regular (-ed) forms for the past tense of verbs. In this study we
quantify the extent of verb regularization using two vastly disparate datasets:
(1) Six years of published books scanned by Google (2003--2008), and (2) A
decade of social media messages posted to Twitter (2008--2017). We find that
the extent of verb regularization is greater on Twitter, taken as a whole, than
in English Fiction books. Regularization is also greater for tweets geotagged
in the United States relative to American English books, but the opposite is
true for tweets geotagged in the United Kingdom relative to British English
books. We also find interesting regional variations in regularization across
counties in the United States. However, once differences in population are
accounted for, we do not identify strong correlations with socio-demographic
variables such as education or income.
