Question

How to segment documents into phrases in text mining using R?

Answer 1

You can use quanteda package. The package is designed for R users needing to apply natural language processing to texts, from documents to final analysis. Its capabilities match or exceed those provided in many end-user software applications, many of which are expensive and not open source

Answer 2

You can do this in R using the quanteda package, which can detect multi-word expressions as statistical collocates, which would be the multi-word expressions that you are probably referring to in English. To remove the collocations containing stop words, you would first tokenise the text, then remove the stop words leaving a "pad" in place to prevent false adjacencies in the results (two words that were not actually adjacent before the removal of stop words between them). please follow the below link you can get clear idea. 

Comments

Thanks @Sandeep, I'll try the quanteda package.