@Tiziano dos Santos - you could perhaps use strsplit to split the string on the space character and will create a cell array of strings (the words from your sentence). You could then use join to combine the words with a space between each one (may also need to trim the string first).
There is also probably a clever (better way to do this using) regexprep command that will do the same thing. I tried it and it wasn't too difficult to do.
