Alternative Hunspell dictionary for stemming
I can't comment on your question (my reputation isn't high enough), but I've got a few clarifying questions to ask: Why do you want to stem words?  Text classification?  Sentiment analysis?  Something else?

I've used both the 'tm' package and the 'RTextTools' package for stemming when doing text classification.  Both have some built-in functions for stemming.

Whether they would be useful to you or not depends on why you want to stem words ... 

FWIW, here are some links related to those packages:


tm: https://cran.r-project.org/web/packages/tm/index.html
RTextTools: http://www.rtexttools.com/documentation.html