Sigmund Freud believed that we have a mind of which we cannot be conscious, and that this mind works continuously beneath the activities and perceptions of everyday life.  He is joined by his one-time colleague Carl Jung in the belief that the work of this unconscious mind sometimes can be glimpsed in dream symbols or even in 'free' associations or chance phrasings.  This capability, if it exists, would be mythic in the sense we used the word here, in that the voice that speaks within these images and words is a voice in all men and women. 

Before we get lost in this, let's go back to Father Flynn's words to his young friend:

"I am not long for this world."

Let's assume that this is not just a statement about the Priest's physical health. What messages could be in it?  Stop being logical; see things said, things almost said, things implied and things almost implied when the sentence is spoken in different tones and with emphasis placed on different words--as we might in conversation.  How different the meanings are:

I am . . .           (just a pause)

I am not...         (just pause)

I am not long... (pause, creating the implication that there is something left out. Could it be ing ?)... ing for this world.

I am not long for his world.   --leaving out the T, as Eliza laments she must do, now that he is dead ("I won't be bringing him in his cup of beef tea any more")

I am not longing for his world.

I am not long for his word.      -- leaving out the L that would complete him.

I am not longing for his word.  

Some people think this kind of thing is nonsense.  But as you finish the story, ask yourself, how many of these apply to Father Flynn? 

Can you imagine Joyce picking particular phrases because of tones and associations hidden within them?  Is this how he creates the unconscious mind of his characters? Before you dismiss the idea, you might look at the changes he made to his first draft of the story, with that in mind.