BNHA is obviously set in Japan, but many villain fans speculate if any LOV members speak English as well. Here are my thoughts about it as an English as a Second Language teacher.
Shigaraki– Based on his upbringing, I'd say he probably has a damn good grasp on reading and writing in English, possibly even listening comprehension, but he has no conversational ability whatsoever. As someone who intended to take over the whole world, AFO would've wanted his heir to know English. However, Tomura's extremely secluded childhood meant that he probably wouldn't have had the opportunity to converse in the language or work on his pronunciation.
Dabi- Little to no ability. His education stopped at early middle school a decade previously. He might still be able to say "Hello. My name is Touya. I am from Japan. Do you speak Japanese?" if he'd had those stock phrases beaten into his head during his education.
Toga: See Dabi. She might have a few more phrases memorized since she's more recently out of school than Dabi is. "My favorite color is red. I am 14 years old."
Twice: No ability. Like Dabi and Toga, he also dropped out in middle school. He's older than they are, though, so he's had more time to forget anything he'd learned at school.
Spinner: Shockingly, I think he's the most likely member to be decently fluent in English. If I remember correctly, he finished high school and therefore had at least 3 more years of formal English education than the rest of them did. He's also a young guy who plays video games, which in my experience is a demographic that rapidly gains English skills from playing online with Americans. Shigaraki is explicitly said to have only played solo, but Spinner could've played online. His English conversation skills are probably really good and he's learned every curse word and slur that there is, plus a bunch of idioms. He might not be great at reading and writing in English unless he joined Discord or Tumblr or something.
Compress: Unknown. He's been out of school for a long time, but it seems like a random skill that he'd have.
The issue with overhaul is what he did to Eri. No amount of sob story fixes that
Of course nothing fixes what he did, but nothing will fix what any of the villains do. Yet, Shigaraki, Toga and Dabi are seemingly being set up to be saved, and the manga going toward a 'everyone deserves to be saved' message. If that's the case Overhaul should be saved too, and it's kind of bizarre that Hori ignored him, despite him being a really good first candidate for a villain being saved.
And sure, what he did to Eri was unforgivable, and she is under no obligation to forgive him, neither is Izuku, but at this point it's almost cruel to not help him. Unlike Shigaraki and Pals, Overhaul is defenseless. He is a danger to no one, and can barely function. He is a broken man, who just wants to fix his dad.
There are logical reasons why Izuku or any of the Heroes continue to have giant, violent fights with the LoV, particularly Shigaraki. I can't fault Star for trying to kill Shigaraki, or not trying to reach out to a person who has not just leveled a country and is trying to rule the world, but is also actively trying (and succeeded) to kill her and steal her power. Despite what the stories themes are, I don't think it reflects badly on someone to defend not just themselves but billions of people from a really terrible fate.
But that's not the situation with Overhaul. Yes, he hurt Eri, but he's not doing it now, and physically and mentally can't harm anyone. Continuing to deny him basic human decency and lock him back up in prison is kind of terrible. I mean, I was floored that Izuku didn't even seem shocked by Overhaul's state. This is the guy who turned himself into a huge ass monster to kill him, and now he can barely hold a conversation because he's been so fucked up.
I just don't understand how Izuku can see a small child in Shigaraki, who is actively trying to kill him and everyone he loves and decide to save him, but not look at a disabled man that is mentally not all there anymore and not feel anything. If the point of this manga is that villains are people, and that Heroes save everyone, regardless of what they've done, Overhaul should not only count, he should be a wake up call for Izuku.
And it's not like he hasn't forgiven abusers before. I mean he defended Enji's right to change and be a better person to Dabi--the kid Enji neglected until he set himself on fire. How is Overhaul somehow not deserving of the same chance?
If Shigaraki and Co. get to be happy after all the horrible things they've done, why is Overhaul excluded? Especially when he has a similarly tragic past and a super tragic present?
Sob stories can't be a factor when it comes to someone actively trying to hurt you or someone else, but that's no longer the case with Overhaul. Helping him and treating him with basic human dignity is just the right thing to do. Letting him suffer doesn't fix what he did to Eri anymore then treating him humanly does.
I'm not saying Izuku should be his best friend, all I want is for him to see Overhaul's humanity like he did Shigaraki's--because saying everyone deserves to be saved is a far better message then saying only a select few deserve to be saved.