Science fiction and fictional royalty are no strangers, with various planets adorned by exotic and varying degrees of pompous monarchies.
When one addresses royalty, especially in fictional settings, you run the risk of insulting the Majesty and ending your days being fed to mutant wild-life, absorbed into cosmic matter or turned inside-out.
So, reading through the scripts for Star Wars, I encountered that the ways with which styles and titles are used in regards to the royalty in a Galaxy Far Far Away, are less consistent, less in tune with real usage and, I ought to add the prefatory remark that I am very much aware that it is a work of fiction and that ultimately a fantasy work like this has its own rules, but still, nevertheless, Star Wars being owner of many foibles - especially in regards to the Prequels - I venture on.
Linguistics is after all the pursuit of this blog, and I may very well have my try and taking an analytical light-sabre strike at the saga from my personal vantage point.
Queen Amidala is the first monarch that we encounter if we are to take the internal narrative's chronology, i.e. Episode 1 and onwards. She, if everything was prim and proper, would be referred to as Your (Royal) Majesty, but things like consistency are a curious thing in the Star Wars universe.
Queen Padme Amidala, who is also referred to by a dynastic surname rather than forename, is referred to in the following ways:
Your Highness: 24 times.
Your Majesty: 10 times
The only two people to refer to the Queen via her proper title are Senator Palpatine (whose style themselves are a veritable nightmare, which we will touch upon shortly) and Jedi Master Qui-Gon Jinn. The former being a pecksniffian manipulator whose usage of the right form seems to suggest less sticking to the decorum and more about being eerily unctuous. Her office is that of an elected monarch and as such she is deservant of the proper title as any other king or queen of a country would have, regardless of her inheriting the position or being elected for it.
One could posit that the Nabooians themselves are positively confused as to what is the right form of address to the Queen herself - hence only the Senator and a member of an intergalactic order of warrior-monks apparently knowing how to adhere to protocol.
All of them use "my lady" after she abdicates her position in favour of becoming a senator herself, thus earning the proper formal style of "Your Excellency," and on the very topic of Excellency, before we move on to old Sheev, we need address the discombobulating matter of titles of nobility and royalty within the Star Wars universe which is thrown about indiscriminately, let us not get started on how an interpreter-robot can be human-cyborg relations.
Arch-Dukes, Barons, Bosses, Caliphs, Counts, Emirs, Emperors, Grand Viziers, Kings, Princes, Princesses, Queens, Viceroys and so on, all of these are actual real world titles and as such do have some sense of meaning to them, however they are thrown around as if given out at a grand galactic lottery for aristocrats. Dooku is the hereditary count of his home-world Serenno, hence Count Dooku, why the hell an entire planet constitutes a county boggles the mind. Counts were typically given land or area by virtue of a monarch granting them it, did Dooku's ancestors do any favours for any ancient rulers? Those astro-political questions are beyond the scope of this article.
Returning to Emperor Palpatine, he is various referred to throughout the past and present media as "Excellency", "Highness" and "Majesty", the former more proper for his former status as senator, the middlemost being either a flub or an insult from Luke Skywalker and the latter being the proper way to refer to an emperor.
He is also referred to as Your Excellency within the narrative frame of Star Wars Episode II - Attack of the Clones, by people such as Anakin Skywalker, the later Lord Darth Vader, where Palpatine is "elected" the Supreme Chancellor of the Galactic Senate.
"Lord" and "lady" and to that point also "master" are the most stable of the titles used within Star Wars, the former two being generic honorifics used for nobility or people of power and the latter for Jedi/Sith masters, in the sense of a teacher and their apprentice.
Darth Vader, whereof "Darth" would one assume is the title assumed by a person when they become a Sith and the other half being some sort of pseudo-ominous nickname, hence Sidious from "insidious" and Tyrannus from "tyrannous." If you look at the earlier drafts for Episode IV - A New Hope and just take the film on itself, separate from the sequels and prequels, then it is revealed that "Darth" is in fact the forename of the character, hence Obi-Wan Kenobi calling him by this in the film - retroactively changed to be Obi-Wan reminding Vader of how far he has fallen.
The very name "Darth Vader" stems from the phrase "dark water" and hearkens back to George Lucas' creative nomenclature when naming the characters in the story, going more by what sounds best rather than the meaning of the name. Only through the serendipity of Vader quasi-sounding like Germanic words for "father" and "darth" halfway looking like "dark" do we get what is later spuriously claimed to be the official etymology.
Vader is furthermore apparently derived from the name of Gary Vader, one of Lucas' old acquaintances from his high school days - who purportedly bullied Lucas' younger self, hence it being an apt name for the main villain of the films.
So, all in all what did we learn?
It's a fantasy tale set in a galaxy far, far away and thinking overly much about the actual etymological, historical and real-life importance of concepts within the Star Wars universe will set it crumbling apart.
Presumably the titles are very much just an homage to the science fiction stories of old and especially the pulp fiction that George Lucas was fond of and created Star Wars as an homage to that golden era of weird adventure fiction, where you would slap an aristocratic title to an intergalactic villain and it would be nothing more than to suggest the ominous nature of them more than anything else.