to think this is normal, or should I/we interfere more

[ReadyForGoodNews]

My two teenagers, DD15 and DS16 are always, ALWAYS arguing. The whole fucking time. We can't be in the same room all of us together without them either muttering insults to each other or just plain out right shouting.
We're having dinner, they argue about who's eating what, how much the other has had etc. If we're playing a board game, one of them is always making fun of the other, taking it too far and then it all becomes a huge argument.
DS has form for always criticising DD. Things like "oh you're a failure", "you're so dumb", "look at her, she's pure evil", "you'll never get anywhere in life", "You always fail at maths" and then whenever she says something about anything, he will SIGH sarcastically, mutter "ugh, idiot"... etc etc
DD on the other hand, loves interjecting all conversations with something mean about her brother: "no one cares what you think", "who said we want to know your opinion", "you have no friends", "yeah right that's so brilliant, you think you're so great", "yeah we really don't know it was you who finished the cake"
Really NOT NICE!!! And I really hate it!!!
DH can't handle it and when it gets to a certain point, he gets upset and tells them off, to which DS replies with a very infuriating satisfied smile and DD acts like a horrified victim and leaves the room.
I try to ignore until I feel it's going to go too far, and I either change the subject, or say something like "enough, if you won't stop it please leave the table/room until you calm down".
This doesn't change the fact that the same happens every day every time they're in the same room. They used to have an ok relationship, normal sibling stuff.
We try very hard to never take sides. DH thinks we have to come up with more strategies and be more involved in trying to change this. But it just seems impossible to talk about this with them at the moment. Whenever we try, they think we're taking the other one's "side". UGH!!
AIBU in thinking this is normal teenage stuff and they'll grow out of it?

Personally I would freak if this has been going on a while, it must be most unpleasant to live with.
A hand up to stop it each time either of them starts and a reminder if they can't say something nice don't say anything at all.
You may end up with complete silence but that may be preferable.

Incidentally I think I'm pretty laid back as a parent.

Oh gosh OP that sounds like a really tough situation. I'm ashamed that my twin sister and I were quite a lot like that when we were growing up. It was hell for our parents, I'm sure.

Are your son and daughter at the same school? Do they have the same interests or different interests? I think when they leave school and go to university or start working, it'll be better for you because they'll see less of each other and have less of a chance to compare themselves.

I was like this with my sister. Now we're adults we're cordial but not close.Same with DS1 and DD, however since she's had children they've become quite close

Siblings don't always get on. Me and my DSis used to bicker quite a lot - maybe not this much - but put a (not very nice) visitor in the house and we would unite against the common enemy, and it all got a lot better when DSis left for uni.
Deep down, there is affection - massive - between us, and it came out when parents died and we had to work together to empty properties and deal with probate etc.
Be optimistic- it's a long game. Hope for the best!

Rudeness jar? £1 in for every rude/wind up comment heard by you, jar contents to be spent on wine for the parents?

You can't make them like each other, but you can insist on civility.

Take their phones until they can be civil to one another?

put a (not very nice) visitor in the house and we would unite against the common enemy

Haha same Bluetrews25! 😂

That sounds toxic!!

How do you and DH talk to them and each other generally? And when they were growing up? It doesn’t sound like they know how to interact respectfully. Like they don’t even know that’s an option.

I don’t have teens yet so no idea if this will actually work, but I agree with stayathome about challenging every nasty remark and saying if you aren’t saying something kind don’t say anything.

Personally I’m not a fan of ignoring attention seeking behaviour. I think if your kid is playing up they are signalling they need your attention / support - usually about a totally unrelated issue. Have you heard of ‘love bombing’ - google it, blogs etc will explain it better than I can.

Zero tolerance. It’s one thing to dislike, but another to be shitty to someone else. It’s ok to tease good naturedly; it’s not ok to constantly insult and be rude.

The second one starts I cut it off with ‘That isn’t how we speak to people.’ And stick to it.

And speak to each of them separately. Make them think about how they’d feel without the other. They’ve only got each other- it seems so sad to live like that.

Also I’ve read some interesting stuff about changing the focus when you challenge remarks like this.

So instead of ‘stop saying nasty things to your sister’ saying ‘I don’t like it when you are unkind to other people and I don’t want to hear it’. It becomes about your reaction to their behaviour IYSWIM.

Like I say I’m not at this stage yet. I came from an abusive home so I obsessively read parenting blogs and books in an attempt to pick up tactics that are kind and loving.

The book ‘how to talk so kids will listen and listen so kids will talk’ is good.

I’ve heard it said that parenting teenagers is like parenting toddlers but don’t know how true that is!!

Yes they go to the same school but have very different interests, different personalities too. But they've always been ok, only normal sibling arguments from time to time - this insane bickering started a few months ago but I can't think of any change/challenge that might have caused it? Nothing big changed at home or school.

How do you and DH talk to them and each other generally? And when they were growing up?
We are respectful of each other, me and DH aren't in the habit of shouting/swearing etc. And when they were growing up, same. This really isn't how we interact with each other in our family. And I think both DD and DS are perfectly fine with others, teachers, friends, family, never had an issue. With me and DH too when the other one isn't around. That's why I think it's a teenage phase?

I will try the rudeness jar. That might affect DD more since she loves shopping

To be fair I do remember a time when me and Dsis went through a phase like this - I was around 15 and she was 14. But we have a great relationship now so thanks for reminding me, there is hope!!

Family meeting
Tell them they are destroying the family and negatively impacting on your marriage
Zero tolerance from hereon. Any event spoilt by one will be terminated. A game will be over, dinner time, the perpetrator has to leave their dinner and the table immediately etc.

At that age my dad would have sent is away from the dinner table and my mum would have withheld lifts. She also used to tell us to pretend that each other was someone else! Set a consequence, warn them both in advance one time then stick to it.

My two can snip at each other and sometimes get into very heated arguments. They also often spend long periods of time in their separate spaces with zero interaction. They also obviously love and care about each other, and this year with ds at university they have missed each other a fair bit.

The OP's children seem to have gone beyond casual sniping into really nasty behaviour, and while it may be 'normal' for teenagers I am with her dh and absolutely wouldn't want to let pretty much any of those comments slide.

What I'd want to do is to sit down with my dh, decide on where the line was (ie all direct personal insults or attacks) and the decide on the consequences, which to me would be an initial 'I don't want to hear comments like that, if you can't stop then be quiet' followed by a 'leave the room now' and if not complied with then whatever sanctions you normally use, ie loss of privileges etc. Then I'd sit down together with both children and tell them that you have had enough, their behaviour is unacceptable and what you plan to do about it. If either challenge , claim it's all the other's fault etc I'd totally stonewall, say this is how it's going to be, you don't care how they feel about it / who starts it etc and mean it.

I think the rudeness jar will just set up 'but he started it.. well she looked at me... you're an idiot...' and give them another reason to snipe at them.

I take it they have allowances if they would have money to put in a jar? Just don't give it to them if you deem they haven't been polite enough to earn it.

I think you need to get back in control TBH.

So instead of ‘stop saying nasty things to your sister’ saying ‘I don’t like it when you are unkind to other people and I don’t want to hear it’. It becomes about your reaction to their behaviour IYSWIM.
Sorry I know your advice is coming from a good place, but that's got to be the most ineffectual thing ever to say to a sarky, back chatting teen.
I wish I knew the answer though, as mine are like this albeit slightly younger. Afraid to say losing my shit with them is the only way it stops temporarily

and yes absolutely don't engage in any specific discussion about whatever is said and instead use scripts like 'I don't want to hear that', 'that's not an acceptable thing to say', 'I've had enough', 'if you don't have anything nice to say don't say anything at all', 'that's not OK during family time/dinnertime', 'don't be so unpleasant', 'if you can't be civil you can go to your room' etc etc.

I impose silence. "If you can't say anything nice, then shut your flapper."

I have zero tolerance for this sort of thing. I insist that everyone who lives in our house has the right not to be abused in their own home.

Over Christmas youngest DS (11) has started saying "shut up" to people. He tried to insist it was fine because his teachers say it at school. He has been told very firmly that it is not acceptable.

Candle true!

I remember being a teen and getting growing pains and horrendous period pains...plus all the fascination with sex at school and all the obsession with appearance etc. It’s a truly horrible time for a lot of kids and I think sometimes the pressure comes out in family interactions where they are ‘safer’.

Low yes they have allowances so I am thinking "take away £1" every time one of them says something nasty to the other.
To be clear, they don't talk this way to us, just each other they seem to have a problem with at the moment. Maybe reviving some sibling rivalry.

Some good advice here, thank you. A family meeting is overdue.

I remember one of my friend's DCs calling her brother a retard. It was just the once, but she immediately had her next day trip to the barn for riding cancelled.
She never did it again.