Hey anon! Sorry I had to redirect you to my tumblr blog, but as Marshmallow now limited their responses to 1,000 characters only (versus having 10,000 characters before), I do not feel comfortable truncating so much information in solely 1,000 characters LOL.
That being said, here's my lengthy response to this LOL (Removed the Read More cut on June 7th 2025)
Oh anon, there's a lot to cover! And it'd be difficult to list all of the differences especially since some require cultural + historical context and knowledge (and I'll be completely honest, a long time has passed since last touching this game in 2021).
🌟One of the most interesting differences that I feel confident discussing would be the unique personal pronouns used by characters, which add an extra element to their personalities and how they view + interact with other people in their world.
IE: Lucifer and Merky using the archaic 汝 for others and 我 for themselves, some using お主 and other pronouns showing rank/hierarchy, Burroughs using ワタシ in katakana to denote that she's robotic/a program, the contrast between Walter's オレ (+ his casual speech) and Jona's 僕 which later adds an extra element from Jona's initial respectful/amicable demeanor + softer speech patterns VS his shift into extremist beliefs and harsher speech patterns, etc.
🌟Also fun fact: Merkabah's Phase 1 voice is actually pitched up to sound feminine versus Lucifer's Phase 1 voice being pitched down to sound deeper and more masculine. My friends that played this game in ENG were surprised to hear Merky's vocal distortion purposely sound notably feminine in his Phase 1 form in JP LOL.
Personally, I've always believed this is due to Merkabah representing the Divine Feminine and Lucifer representing the Divine Masculine. (spiritual concepts that go beyond human social constructs of gender, sex etc). Even their designs push this idea further and depict this concept literally, with Merky's revealing female chest + curvy silhouette and Lucy showing off his masculine torso as he wears a revealing traje de luces--an outfit from a sport heavily associated with masculinity.
In spiritual contexts, the Divine Feminine and Divine Masculine aspects of your soul come together within yourself to form a "Divine Union", which is the concept of achieving stability, wholeness and balance. Though, a Divine Union can also be extended to include achieving harmony within relationships, etc.
Interestingly enough, you find out that Lucifer and Merkabah fuse to become Satan in SMT4 FINAL. Thus, both Lucy and Merky have achieved their own Divine Union--not to mention how as Satan, they are also effectively the other half of YHVH as well.
See also: "Wounded Divine Masculine/Feminine Traits" to see how those personality traits are just Walter and Jonathan's gradual character progressions into becoming Lucifer and Merkabah too, LOL.
(I actually wrote wayyyy more about this with in-game screenshots from the Neutral Route as well, but ended up deleting it since it was super off-topic LOL. If there's interest, please leave me another askbox message and I'll discuss this a bit further! Especially within the context of Walter and Jonathan's unique relationship. and why I love them so much LOL)
🌟Getting back to the main topic:
The usage of personal pronouns in JP is difficult to properly translate into ENG, especially with some characters denoting their rank or position of power against others. Japanese is a hierarchical language and sometimes has 曖昧/ambiguity that requires reading the atmosphere to perceive indirect meanings. Even within video game text, these things can be tricky to TL into ENG without someone having a strong understanding of these concepts to faithfully translate (or localize) the general gist of what is being said without erasing or heavily editing the original intent.
There's so much more you can discuss, but as I am not 120% fluent in JP, nor am I claiming to be (and I don't ever claim to be an authority figure on explaining these types of things), I definitely encourage you, especially if you are learning JP as well, to look more into the unique nuances + cadence that each personal pronoun has.
🌟Another thing I found interesting was how Luxorors and Casualries, in the JP version, are called "Luxuries" and "Casualties".
Perhaps the change in ENG was to not give away too much of the story, or to perhaps lessen the harshness of the word "Casualty" itself.
→ There's also the potential link between the necessity of having Demonoids and Nourishers VS Mikado having Luxorors and Casualties. It's an interesting brainworm to think about and can imply many things, leaving you wondering about the original true purpose of a Luxoror/Casualry system to begin with LOL (knowing what we know about King Aquila from base SMT4 and SMT4FINAL). Like, the fact that they are so overtly called "Casualties" makes it incredibly obvious of their oppressed status and fate.
🌟And finally, one of the last things I'll mention for now since this is getting super long (LOL) is the very obvious implications of Jonathan being gay and his discomfort with females which got removed in ENG.
(And the whole 「僕は本当は...猫さんなんだぞぉ~」 comment plus the double entendre of calling yourself a 猫 as a gay man)...
SMT has never shied away from double meanings or topics like these, so I've always thought this double entendre was intentional. Like, "if you know, you know".
(The way my eyeballs comedically popped out of my skull when getting to this part of the game when reading this dialogue back then was WILD. I thought I was just being a delusional ワルヨナ腐男子 until coming across THIS LOL.)
🌟There's also the extra audios of the SMT4 JP voice actors from the official SMT4 website that never got TL'd into English. There's a lot of them from different characters, so check them out!
The audio messages on Hiroshi Kamiya's side (Jona's VA) very much indicate Jonathan's discomfort towards women, (and perhaps his family background comprising of 3 sisters having to do with this) and feeling more comfortable admitting certain things around men: https://megaten4.jp/mega_spo/01.html
🌟I remember showing screenshots of the iconic "Let's go to the bakery" scene in the beginning of the game with my friends in 2022 (I literally went back in my Discord history to find this LOL) and they all found it crazy that the JP version blatantly mentioned Jonathan being uncomfortable with the concept of flirting with females.(僕はそんな...女性とだなんて...) whereas the ENG version removed this completely.
I was definitely surprised that the ENG version removed the mention of females to begin with. Personally, I would've translated it along the very rough lines of, "Doing such a thing… with girls…!" (and his flustered sprite obviously giving away that he finds the idea uncomfortable, thus doing more Showing than Telling LOL). There's other moments that show this side of Jonathan more too, which is also again, another story for another time LOL.
🌟In essence: I hope this encourages you to play the game in JP if you're learning the language, and allows you to gain more context regarding their world and a deeper understanding of these characters. Thanks for the question!👋
Admittedly, because I've only experienced the duology in a different language, I feel like I don't have the right to interact with others who like this game too LOL (???) due to these slight differences that affected how I perceive the SMT4 world and these characters, and perhaps that can also explain my own isolationist tendencies. But trust that it does not come from a bad place--rather my own insecurities and anxieties regarding interacting in online spaces LOL. Despite this, I really do appreciate you reaching out and your genuine question. ✊