Tell you what does NOT signify "fear of speaking in public"... Mercury retrograde and/or Mercury combust. Nor does Mercury square Saturn, nor Sun square Saturn.
An afflicted lord of the Third House does not signify fear of public speaking.
Neither does "shy and reticent" Cancer rising.
All of these things are present in my horoscope, yet I have an inherent and natural talent for convincing public speaking. I am always amazed at the power of my public voice. Listeners become followers, converts or tools, at my whim.
With all the negative indications in my chart (conditions and aspects that would seem to impair the ability to speak in public), what is it that DOES show this innate ability? And why do these things (whatever they are) seem to overpower or dominate the conditions and aspects mentioned? What effects do the conditions and aspects have in the personality that may manifest positively through the act of speaking in public?
The chart has a preponderance of Air. The Air element holds the power of communication. It is also the realm of abstract, or symbolic, thought; it is the world of the Idea. In addition to a numerical preponderance of planets in Air, there is an out-of-kilter grand trine in the element which includes both Lights. This weighting of the horoscope toward Air is a general statement made by the horoscope to the effect that the native is in his element in the world of ideas, abstraction and communication (and all the other things implied by Air.) It is a "general statement" because preponderance depends on all the planets in the horoscope taken collectively rather than individually or in small discrete groups (such as "Mercury retrograde and square Saturn.") This latter is specific or particular rather than general or universal as is the case with preponderance, chart pattern and other universal indicators. The universal is dominant over the particular. A particular indication in a given chart must conform to and is subservient to the universal indications in that chart. The particular indications show how the predominant trends will work out.