wordlists
is a named list of character vectors where each list element corresponds to a different readability index. These are:
DaleChall
Spache
Klare, G. R. 1975. "Assessing readability." Reading Research Quarterly 10(1): 62–102.
Spache, G. 1953. "A new readability formula for primary-grade reading materials." The Elementary School Journal 53: 410-413.