Macbeth's Tomorrow speech makes recurring use of a device whereby a line or a sentence will contain a word or phrase with a secondary meaning which is not relevant where it occurs, but introduces a meaning which will occur later. Listening to the speech is an experience like a dream where the merest thought of something can cause it to expand and take over the entire dream.
The most natural reading of the first two lines of the speech, were they to occur alone, would be something along the lines of "It would have been better had she died later, as there would have been time to deal with it properly." The "a" before "time", however, suggests the alternate reading of "It was inevitable that she would have died at some point in the future." It is likely that both meanings would be active to some degree in the mind of the listener. This second, less likely, reading suggests the general tone of the speech, on the inevitability of death. The very word "hereafter" introduces the equating of temporal and spatial position: "hereafter" is after whenever is "here", but "here" alone refers to spatial position.
The phrase "petty pace" seems somewhat odd. It is not natural for a pace to be petty. Since tomorrow "creeps in", we must read "petty" in its meaning as "small", even though "petty" would in almost any other context mean "unimportant" or "trivial". Although the idea of triviality is not present in the line, it is brought to the mind of the listener by the use of the word "petty", coloring our understanding of the rest of speech in the direction of "life is pointless".
Note also that "day to day" sounds exactly like "day today".
Assuming we knew when "recorded time" was, what does it mean for something to continue until the last "syllable" of recorded time? This suggests that recorded time is composed of words. What words might it be composed of? "Tomorrow and tomorrow and tomorrow" seems a good candidate. This is a bit of stretch, but consider I.v.56-58:
Macbeth: Duncan comes here to-night.
Lady Macbeth: And when goes he hence?
Macbeth: To-morrow -- as he purposes.
Lady Macbeth: O, never
Shall sun that morrow see!
If Duncan shall never that "morrow" see, then the "to-" is the end. This seems like a very forced reading to a modern ear, since "morrow" has fallen out of use, and "tomorrow" is a single unit, but it may have been more accessible to an Elizabethan audience. The image suggested by this reading is one of time ending at night, before the morning, which would add to the later idea of fools being shown to their death by candlelight and life being a walking shadow.
"Recorded time", would generally refer to something like "recorded history". While one could interpret "recorded time" to refer to preordained events given the speech's general feel of lamenting the inevitability of death, this interpretation is likely to be overshadowed by the association of "recorded" with history and that which has already happened. One would not normally refer to the "end" of recorded time, but instead to the beginning of recorded time. If recorded time had an end, the most reasonable point to place it would be right now, but the sentence as a whole has a pattern "the last ... of ... time" which immediately brings to mind the idea of the end of the world, the end of time.
The idea of "recorded time", as "recorded history" leads into the next sentence, that "All our yesterdays have lighted fools the way to dusty death,". Although "yesterdays" seems to refer most directly to something like "our past experience", but we cannot help picturing someone or something showing leading the fool to his bed-chamber where he will die. "Way" could be read as either "manner" or "road", but the imagery of "creeping" and "pace" earlier suggests the more literal idea. This provides another example of the association of passage of time with movement in space.
"Fools" would seem to mean foolish people from the context, but it also has the meaning of a jester or clown, which will be echoed later by the player strutting and fretting, and the idiot telling tales.
"Yesterdays" completes the pattern of "to-morrow" in line 19, and "to day" in line 20. It would be interesting to look into how readily available the meaning of "enlightened" as "caused to understand the truth" would have been to an Elizabethan audience. To the modern ear, it's very easy to hear this as saying that by showing the fool his mortality, the fool is enlightened.
I am not able to read the speech without a slight pause after "dusty death". With this cadence, there is a consonance between "Out, out, brief candle" and "a walking shadow", the words "candle" and "shadow" connected by sound in addition to being connected by meaning.
The idea of walking toward ones death may be reinforced by the parallel between "petty pace", the fourth through sixth syllables of line 20, and "dusty death", the fourth through sixth syllables of line 23. Not only are they alliterative phrases in the same position in the line, but the alliterative consonants are both stops, the middle syllable of each is "ti:", and both end with unvoiced fricatives. This may also reinforce the idea of life's futility via the parallel between "petty" and "dusty".
After such emphasis on physical movement and walking, the first thought on hearing the next two words, "out, out" is likely to involve a command that someone leave an area, but when the sentence is done, it has changed meaning to blowing out a candle. This is the candle that has lit the "way to dusty death", so with blowing it out, we would expect to see darkness, and in the next line, "life's but a walking shadow". The modern meaning of "shadow" would probably be initially the most probable, but when the line moves on to "a poor player", it takes on the wider meaning as well.
The phrase "struts and frets" for what life, the player, is doing with his hour on the stage, creates and image, at least for the modern listener, of someone being overly dramatic, unable to accurately portray an emotion and so forced to resort to over-acting to convey what he is supposed to be feeling. This suggests both the "sound and fury" of the "tale told by an idiot" in the next line, and the fool who is being shown his way to death. The player, who "struts and frets", would appear to be performing physical actions, but not necessarily speaking. Thus, it is somewhat odd to say that after the hour is up, he "is heard no more", but immediately after this, another image of life, as a "tale told by an idiot", is presented, which does involve speech. Indeed, we are explicitly told that it is "full of sound and fury". The final line of the speech, "signifying nothing" is the direct suggestion of life being meaningless, but it does not surprise. It has been set up by the "petty" of line 20, and by the general idea of life as a play beginning on line 24.
The equating of movement with the passage of time is a general theme of the speech, and words relating to both ideas occur frequently. For time we have "hereafter" in line 17, "time" in line 18, "tomorrow" in line 19, "day to day" in line 20, "last" and "time" again in line 21, "yesterdays" in line 22, "brief" in line 23, "hour" in line 25, and "no more" in line 26. Only lines 24, 27 and 28 contain no reference to time. Words related to movement occur as "creeps in" and "petty pace" in line 20, "way" (as road) and "out, out" (as "get out") in line 23, "walking" in line 24, and "struts and frets" in line 25. One could also include "lighted" in line 22.
In several places there are references to words or to speaking: "a word" in line 18, "syllable" and "recorded" in line 21, "heard" and "tale" in line 26, and "signifying" in line 28. Coupled with the image of life as a player in line 24, these may serve to make us more aware of the play as a play, rather than as reality, which may either ease our own discomfort at being told that life is pointless (because, after all, we are not players; life is no scripted for us), or it may heighten the seriousness of Macbeth's condition: he is condemned to do exactly what he has done, again and again, as the play is written. It may do neither of these.
In addition to this form of semantic self-similarity, the speech has a great deal of less meaningful patterning which in general makes it seem more a single piece and more pleasing to the ear. The phrases "she should", "petty pace", "dusty death", "poor player", and "tale told" all alliterate. "His hour" does not alliterate in my pronunciation, but may for some. At least with modern pronunciation, the rhythm brings together "out brief candle" and "walking shadow". The rhyme between "yesterdays" in line 22 and "way" isn't as forced by the rhythm and may not be noticeable. "Struts and frets" parallels "sound and fury", and "full of sound" alliterates with "fury / Signifying". There is, no doubt, much more to be found.