Gestures Fix Everything?

So it would seem that Richards, Ogden and Locke all have one major issue with language that they hold in common in that the signification of words fails when what the speaker says does not hold the same meaning for the listener as it does for the speaker.  Richards and Ogden use the word "thought" or "reference" to talk about what Locke calls the "signification" or true meaning of the word while describing words themselves as "symbols", but their complaint is all around the same.  In the Richards and Ogden text point out that people, upon hearing someone speak, tend to assume "that the speaker is referring to what we should be referring to were we speaking the words ourselves" (1276) and that although sometimes this interpretation is correct and understanding is achieved, it is usually not the case.  Okay, so when words like "love" or "justice" are dropped into conversation, the meanings of those "symbols" or words might have different "signification" or "thought-reference" for the speaker than they do for the hearer.  

But then Ogden and Richards bring up something interesting that Locke never mentioned in his essay, and so it caught my attention.  When they talk about the interpretation of assuming that the hearer and the speaker are thinking the exact same thing, they mention that it may indeed happen at some points, but then go on to say that "in most discussions which attempt greater subtleties than could be handled in a gesture language this will not be so" (1276-1277).  A gesture language?  Where the heck did that assessment come from, and what is it exactly?  They explain it a little more by discussing our own use of this gesture language, saying that "our own subsidiary gesture language, whose accuracy within their own limited provinces is far higher than that yet reached by any system of spoken and written symbols" and also pointing out that "words, whenever they cannot directly ally themselves with and support themselves upon gestures, are at present a very imperfect means of communication" (1277).

So gesture language is something that supports and gives additional meaning to "symbols" and "reference"?  Are the authors referring to body language and the physical gestures that accompany words in our everyday speech, and if so, why do they attribute such high praise for it?  Is a potential solution to our language problem perhaps fixing gestural support for the words that so far lack it?

I'm not sure why they brought up this gestural language, whether to offer it as a possible solution tool oct just to emphasize that spoken language is never enough, I'm not sure.  It just seemed so random, and then it doesn't really get mentioned again.  Thoughts?