It's how to memorize the toughest line in any script. It's a personal invention, but it's worked remarkably well for many other actors too, and it will work for you if you're willing to try it.
Learning scripts word for word is usually more boring than challenging for actors, but there are always some lines in every play script that trip you up. Whether because the words or grammar are unfamiliar, the semantics and sentence structure arcane, a peculiar alliteration that turns it into a tongue twister; or just because; as every actor knows - some lines are tougher than others. You may stumble on them from long before the first rehearsal straight through to performances. You may be off book except for a single critical line than you bumble over nearly every time. You practice it, and you practice it. you thought you knew how to learn lines, but somehow when the moment comes, it gets tangled up all over again. The director was impressed with you, but now this is starting to irritate him... maybe he thinks you're lazy, but that's not it, it's just this *#$^@!! line...
You don't have to abandon your budding career in theater. It's just time for some "staggered memorization", concentrating for a while on just the line that's fighting back.
Let's say the problematic prose creating the mental block is "No annihilation is indecent for this antediluvian." You want to kill the playwright, but he's the producer's nephew, and he thinks this is the best thing he's ever written. Or worse, he's already dead. So instead of violence, let's try staggered memorization. Use all the techniques below, going through them in sequence, for each line that's in trouble:
Technique one:
Start at the beginning of the line saying one word of it, then two, then three... etc, until you get through the whole line:
"No"
"No annihilation"
"No annihilation is"
"No annihilation is indecent"
"No annihilation is indecent for"
"No annihilation is indecent for this"
"No annihilation is indecent for this antediluvian."
Technique two:
Start at the end of the line saying one word of it, then two, then three... etc, until you get through the whole line, including the beginning:
"antediluvian."
"this antediluvian."
"for this antediluvian."
"indecent for this antediluvian."
"is indecent for this antediluvian."
"annihilation is indecent for this antediluvian."
"No annihilation is indecent for this antediluvian."
Technique three:
Start in the middle of the line saying one word of it, then two, then three... etc, until you get through the whole line, first adding a word that's earlier, then one that's later:
"indecent"
"is indecent"
"is indecent for"
"annihilation is indecent for"
"annihilation is indecent for this"
"No annihilation is indecent for this"
"No annihilation is indecent for this antediluvian."
Yep, this is hard, and it may make your head hurt a little. But that's most of the point, to make sure that whatever angle you come at the line, you can handle it, and in particular, wherever you get stuck, you can keep going because you've memorized the line from that point on, so just keep hammering away at your block with staggered memorization until it's gone.
Now, I've written all these iterations out here, but it's important to do this in your head, 'cause the struggle's where the learning is. Maybe writing them out once or twice would help, but doing the task mentally works well - and it's something you can do in odd moments during your day; waiting in line, making yourself coffee, etc. You may want to carry around a small list of the most awkward lines so that you have them to work on, and so that you don't memorize them in some part incorrectly.
I suspect that part of the reason why this works is that we often make the task of memorization a bit too easy on ourselves, coming at each line in almost the same way, with the same mood, cadence and rhythm every time, in a rote way when we're running lines. Such habits make a kind of shallow rote memorization easy, when we're learning lines by ourselves. When there are other actors involved, and props and blocking, not to mention listening and actually acting the line, all those factors that have been the same while we were learning lines initially, are changed, and we lose the line.
I suspect that the more difficult a line in a script is, the more stereotyped our approach to it becomes, which aids shallow memorization, in the context of running lines, but doesn't create a robust memory that will pop up easily in any context.
So perhaps staggered memorization works because it breaks up our rigid habits of how we approach the line, and how we say it. Staggered memorization forces us to memorize the line in many ways, many rhythms, and many moods - even when we're frustrated and fumbling. Perhaps state specific learning is involved, in some small way. Bottom line, it hurts the head to approach a line with staggered memorization but it works. You won't like the lines that are giving you trouble any better, but you won't stumble over them either.