title: Not able to see single digit/letter as a term in after creating TermDocument Matrix
body: <p>I used <code>TermDocument</code> Matrix in R, and documents(strings) include single letter words also. After using <code>TermDocument</code> Matrix, the terms do not include those single letter words, please suggest which control should I include as an input argument in order to include single letter word in my term document matrix.`</p>