Politeness and Formality
I had a hard time wrapping my head around honorific and humble Japanese at first, but working through the chapters on it in Minna no Nihongo really helped me a lot! I definitely would struggle a bit with producing it, but I don’t think I have trouble recognizing it and telling the two apart when I see it in native media (hearing it can be difficult, though, as I often get a bit lost in all the extra syllables… 
).
I have a super fun example of this from pro wrestling! There’s a wrestler in Tokyo Joshi Pro Wrestling called 沙希様, which Mr. Haku romanizes as “Sakisama” because the 様 is just part of her name, haha. Her character is a joke that’s a bit hard to explain… She’s portrayed by a DDT wrestler named Saki Akai (the woman in my profile picture!), but Saki Akai and Sakisama are considered completely different characters in kayfabe and have separate backstories, though other wrestlers will occasionally point out that they look remarkably similar…
In any case, Sakisama is VERY elegant, and she absolutely uses extreme polite speech to add to that effect. When I first translated her over a year ago, the keigo went almost entirely over my head, haha, but I totally caught what was going on when I translated her most recent post-match comments! It’s a fun challenge trying to figure out how to convey this in English.
(This is from TJPW Grand Princess on March 18, 2023)
Hard mode: here is the video of Sakisama and Mei Saint-Michel’s post-match comments. The transcript of the Japanese is from shupro; the translations are all mine and might contain errors.
(Note: Sakisama typically spells 試合 as 試愛, which the transcriber has faithfully reproduced here, haha)
沙希様「久しぶりのここのおリングだったわけだけど、ワタクシたちおリングは久しぶりじゃないの。いつもおリングに囲まれて生活してるわけ。でも、久しぶりにここに立って、少しだけワタクシも気分がよかったわ。メイ・サンはどんな気分だった？」
Sakisama: “It has been a while since we’ve graced this ring with our presence, but you could hardly call it our return to the ring. Every day we are always surrounded by rings. But, standing here for the first time in a long time, I dare say it was somewhat pleasant. Mei-san, how did you feel?”
メイ・サン「ウィ。ワタクシ有明コロシアムとやらで、とてもうれしゅうございました。ワタクシはあとは、あとは…お台場？とやらが近いとお聞きしました」
Mei-san: “Oui. I am very pleased to be at Ariake Coliseum. And, and… Odaiba? I heard that it was very close.”
沙希様「そうよ。お台場には謎の大きな大きな球体があるそうよ。ワタクシはその中に何が入ってるか調べなきゃいけないわけ。（今回はしばらく滞在する？）ワタクシたち、まだ明日の予定も決まってないの。すべて気分なわけ。メイ・サンがお腹空いてれば試合に出ないし、お腹いっぱいだったら寝ちゃうし。気分屋さんなわけ。（フランスでは試合していた？）ワタクシたちは毎晩、お屋敷で舞踏会という…今日、お試愛をしたけどリング上で踊ってたわけ。みなさんもご覧になってたと思うけど。それがお試愛みたいなもんよ。今回、お台場より行きたいところある？」
Sakisama: “Yes, indeed. It seems that there is a mysterious large globe at Odaiba. We have to find out what is inside of it.”
(Will you sojourn here for a while this time?)
“We still have yet to decide on our schedule for tomorrow. It depends entirely on our mood. If Mei-san is hungry, she won’t participate in the match, and if she’s full, she’ll go to sleep. She’s a moody person.”
(Did you have wrestling matches in France?)
“No, but we hosted a ball at our estate every evening. Today, we had a match, but we were dancing in the ring. I think everyone was watching. A ball is like a match. Is there anywhere you want to go besides Odaiba this time?”
メイ・サン「あとは…ワタクシはなんだかあのあたりにガシーンガシーンといった巨大なロボットがあるとお聞きしました」
Mei-san: “Besides that… I heard that there was a giant robot stomping around there somewhere.”
沙希様「等身大のような予感がするけれど、それはどこかしら。ちょっとワタクシたちが調べなくちゃいけないんじゃなくって。行きましょう、メイ・サン」
Sakisama: “I have a hunch that it’s life-sized, but I wonder where it is. You’re saying we should investigate it? Let’s go, Mei-san.”
Incidentally, (spoiler for the next section! 
) the example above is the only example I can find of かしら getting used in my translations (though again, I cannot stress enough that Sakisama is putting on a very certain character with her speech patterns). かなあ also has just one use in my translations.
Sentence-final Particles
I totally got thrown in the deep end with these when I started translating wrestling, haha. I still make mistakes, especially when I don’t catch the intonation (here’s a video on that. Highly recommended watching!), but I am starting to gradually get better at it.
As far as gender stuff goes, I can definitely say that I hear な pretty frequently in TJPW, so women definitely do use it in some circumstances! Same with ぞ (and ぞー for that matter…).
Here's an example with several sentence-ending particles, featuring Hyper Misao and Shoko Nakajima's comments after their match at TJPW's January 4, 2023 show:
Hard mode: here’s the video if you want to try to listen for them.
中島「引き分けだとお？」
Nakajima: “A draw, huh?”
ミサヲ「ドローだとお？ 引き分け？ いや、ドローじゃない。どっちも勝者だ」
Misao: “A draw? A draw?? No, it’s not a draw! Both of us are winners!”
中島「どっちも勝ちなんてあるのかあ？」
Nakajima: “Is there such a thing as both sides winning a match?”
ミサヲ「どっちも勝ちなんてあるのかあ？」
Misao: “Is there?”
中島「まぁでも可愛いウサギさんがね3匹手に入ったんでね、まぁいいんじゃないですか」
Nakajima: “Well, we got three cute bunnies, so I guess it’s alright.”
ミサヲ「そうっすね」
Misao: “I guess so.”
中島「トーナメントあるしな」
Nakajima: “There’s that tournament, huh?”
ミサヲ「トーナメントあるしここでどっちにも黒星がつかなかったことは大きいんじゃないか？」
Misao: “There’s the tournament coming up, so it’s important that neither of us got a loss here, right?”
中島「そうだね」
Nakajima: “Yes!”
ミサヲ「我々どっちも負けてないから」
Misao: “Neither of us have lost yet.”
中島「２人とも初白星～！」
Nakajima: “We both got the first win!”
ミサヲ「とにかく絶対に勝ってやるぞー！」
Misao: “In any case, we’re definitely going to win!”
中島「勝ってやるぞー！」
Nakajima: “We’re going to win!”
Sound Symbolisms
The bane of my existence as a translator 
. I still struggle a lot with these, and no amount of reading about them has really helped, haha. I’ve just gradually gotten a sense for them by exposure. A few in particular appear over and over again in TJPW, like キラキラ (it’s always spelled in katakana in the transcripts).
Here's an example from the TJPW Tokyo Princess Cup finals on August 14, 2022:
No video for this one, sorry! This is from Yuka Sakazaki’s promo in-ring after she beat Miu Watanabe and won the tournament. The translation is mine, though I had Mr. Haku’s live translation thread on twitter to reference, so some of the wording is his. Look for ギラギラ, キラキラ, and ぐしゃぐしゃ!
坂崎「…夏に勝ったぞー！ ９回目のこのトーナメントで、メンバーが減ったり増えてるなかで、こんなにみんな強くなってて…めっちゃだるいけど、めっちゃ嬉しいです！ やべーよ、アイツ！ どんどん選手層も厚くなってて、一人一人がギラギラしてて。キラキラだけじゃない東京女子も見てもらえたかなと思います。夏に嫌われ続けた女がこうやって新しいトロフィー…ちょっとピンクで気にくわないけど、でもこんなトロフィーが私の中にあって、とっても嬉しいです（涙）。でも今回のトーナメントで結果私以外は悔しい思いをしたみんながいて。トーナメントに９回出てる山下とか中島が負けてる姿を見て、私の中でもなんか変わるものがあって。すごい、このトーナメント中に心が揺さぶられました。感情がぐしゃぐしゃになって…なんて言えばいいのかな（涙）」
Sakazaki: “I surpassed summer! This is my 9th time doing this tournament. Members have come and gone, but overall the roster has gotten so much stronger… It’s lame, but I’m so happy! Holy shit, Miu was so tough! The bracket just keeps getting tougher and tougher, and everyone is shining. I hope you were able to see a side of TJPW that isn’t just sparkles. The woman who hated summer got the new trophy. The pink makes me a little bit sick, but having a trophy like this, it makes me so happy (cries). But the end result of this tournament is that everyone feels frustrated except for me. Yamashita and Nakajima have participated in the tournament nine times, and when I saw them lose, something changed inside of me. My spirit was so shaken during this tournament. My feelings are so messy… what can I say (cries)."
Part of the learning curve with these for me has been not only learning the Japanese meanings, but figuring out how to translate sentences containing them into things that we would say in English…
Viewpoint
Another tough one for me, due to the tendency Japanese has of omitting personal pronouns ! I feel like I can figure it out maybe like 95% of the time? 自分 in particular has a tendency to trip me up…
Here's an example with two 自分s (with the same viewpoint, but different speakers) from Nao Kakuta and Hikari Noa's post-match comments after TJPW's March 22, 2023 show:
Hard mode: here’s the video! The portion transcribed below starts around 1:55.
角田「だってまさに今日、私はそういう気持ちで絶対自分が勝って、一番に動くんだって思ってたところで。家にいて、起きたところからWBCを見て。昨日の試合も負けちゃうかもってところから勝って、今日もギリギリのところで勝って。泣きました。すごいって。野球ってあんまり見たことなかったけど、スポーツってこんなに人の心を動かすんだって思ったんですよ。めちゃくちゃ感動した。だから私もそういうプロレスラーになりたい。瑞希さんは私は目標とする、そういうものを持ってる先輩だから。一番私が思ってるから行きたいって思って、お願いしました」
Kakuta: “Because that’s totally how I felt today. I thought I’d definitely win and then be the first to make a move. I was at home, watching the WBC from the moment I woke up. Yesterday’s game, too, I thought we might lose, but we won, and today we won just at the last minute. I cried. It was amazing. I had never really watched baseball before, but I realized how much sports can move people’s hearts. It really moved mine. So I want to become a pro wrestler who can do that. Mizuki-san is a senpai who has this quality, which is my goal. I wanted to step forward because I was thinking about it the most, so I asked her.”
ヒカリ「…はい。そういうとこ。なんか奈穂さんの気持ちが前向きなことを聞いて、今日は奈穂さんに託してみようかなって私は思って。いま絶賛舞台の稽古中ってこともあって、ホントに休みもなく動いてる中でこういう決断をできるのはホントに奈穂さんどんどん強くなっていくなって。かっこいいなって思うし、自分も二足の草鞋で闘ってる中で挑戦したタイミングでも私は心を動かされたので、きっとタイトルマッチはとんでもない角田奈穂が出てくると思います。応援してあげてください」
Hikari: “…Yes. That’s how it is. I heard that Nao-san was feeling optimistic, so I thought I should leave it in her hands today. She’s in the middle of rehearsing for the stage, and the fact that she can make a decision like this while she’s doing all of that without taking a break, she’s just getting stronger and stronger. I think she’s cool, and I was really moved by her challenging while she has so many irons in the fire. So I know for sure that this title match is going to bring out an unbelievable Nao Kakuta. Please give her your support!”
I have no idea if all of the wrestling examples are helpful or if they’re annoying, but I figured they have the advantage of having text and audio options (well, most of them do), plus some sort of translation, haha .