Hello Emad. I used the software (antwordprofiler) mentioned in the link below before a few months for a discourse analysis assignment. Give it a trial and check other apps available on the same website.

See the attached file.

Good luck

http://www.laurenceanthony.net/antwordprofiler_index.html

This is how you cited it:

Anthony, L. (2013). AntWordProfiler (Version 1.4.0.W) [Windows 8]. Tokyo, Japan: Waseda University. Available from http://www.antlab.sci.waseda.ac.jp/

http://www.laurenceanthony.net/antwordprofiler_index.html

In addition to AntWordProfiler, you might consider AntConc or one of the other tools that I have developed. They are all listed in the link below.

I've attached the help page for the latest version of AntConc.

http://www.laurenceanthony.net/software.html

have a look at the lexical chain identifier: https://www.lt.informatik.tu-darmstadt.de/de/software/lexical-chains/

Try http://lsa.colorado.edu/