"A barrier to communication is something that keeps meanings from meeting......." This is quoted in loads of publications but none of them reference it. Where does it come from?
You seem to be asking what piece of writing by Reuel Howe contains the quoted language. The answer to that question is that it comes from Reuel L. Howe, The Miracle of Dialogue (originally published in 1963), page 23. Although access to this book through Google Books is limited to a snippet view, I've combined a few snippets to give you somewhat more context. Here is part of the (very long) paragraph in which the quoted sentence occurs:
A barrier to communication is something that keeps meanings from meeting. Meaning barriers exist between all people, making communication much more difficult than most people seem to realize. It is false to assume that if one can talk, he can communicate. Because so much of our education misleads people into thinking that communication is easier than it is, they become discouraged and give up when they run into difficulty. Because they do not understand the nature of the problem, they do not know what to do. The wonder is not that communicating is as difficult as it is, but that it occurs as much as it does. Education, training for leadership, preparation for marriage and parenthood, should at least give people an understanding of the nature of communication, how it occurs, and how they may carry out their responsibility for it. Many leaders, educators, and ministers—not to mention others—however, go into their work without any adequate understanding of the nature of communication or of the barriers that have to be broken through in communication; instead, they have the mistaken idea that the mere desire to say something is enough. Any process or training that sends men to the task of communication without some rudimentary understanding of it or with false expectations for it is cruel and irresponsible and only serves to condemn them to being disillusioned and disheartened later. While there is more to communication than appears on the surface and more obstacles in the way than we like to acknowledge, it is, nevertheless, true that words need not be spoken in vain. Barriers to communication can be broken through. Meeting of meaning can occur, and through the meeting relationships can be established, even raised from the dead.
There are no earlier matches in Google Books for the wording "A barrier to communication is something that keeps meanings from meeting," which suggests that Howe is indeed the originator of the expression.