whether to use the stemmed, canonical form of the word
(i.e. 'cat', for 'cats') instead of the actual word. FALSE by default.
Note that for pronunciations specifically, setting it to TRUE may get a wider
range of pronunciations; you should experiment.
...
further arguments to pass to httr's GET.
Value
a data.frame of 3 columns: word (the original term),
type (the type of relationship) and related_word.