How much say should parents have over others using diminutives

When they are babies and toddlers - complete say.

once they go to school - it’s up to their pals 100%

With family - you have some control. Once they are at school - much less so.

I only have one child with an obvious shortening or nickname type name (think Robert- Bob, Bobbie, Rob) and funnily enough everyone in the family just sticks to his full name. But sports clubs have often shortened it and that can be helpful when there are other Roberts in the team. He becomes Rob at rugby but Bobby at tennis for example. He’s happy being called whatever… once a child is old enough o have an opinion, theirs is the only one that matters tbh.
@Namiemcnameface those family members changing the grandparents names are ridiculous. My parent became Gran and Grandad when the first grandchild was born and that is what they have to be called by all
future grandchildren!!! Surely that only makes sense.

I think it depends on the child’s age and if they have expressed a preference themselves. My son is 3 and has a name that is commonly shortened, but because we prefer the full version we only ever call him that. As a result he will only turn around if someone says his full first name because he has no idea that the short version is supposed to be his name. He is autistic and has very limited functional language, so he cannot explain to people himself that he prefers his full name. So I do ask people not to call him the short version because he won’t respond to it. I would be a bit annoyed if people ignored me and kept calling him by the short version anyway, because I know he doesn’t like it and just can’t tell them himself. If when he’s older he decides to use the shortened version, that’s his decision and I should have no say at all.

Your best way IMO is to say 'This is Bobby' when he is introduced to people.
They can then ask if he has a middle name, then you could say 'His full name is Robert William Robson but he'll be known as Bobby'.

When one of mine was small she couldn't say her full name and the abbreviation she used was cute for a 2-3-4 year old. One close relative still calls her that when she's a teenager, even though they have been told that she does not like it any more. I feel that is disrespectful, but the relative sees it as being affectionate.

Naming a baby is the parents choice. That includes abbreviations/nickmames. However, unless you are with family a lot of the time, you just gently correct. 'Silly Grandad's calling you the wrong name/nickname again' until the kid is old enough to choose. Or until a random nickname emerges eg Simon loves Biscuits and becomes Biscuitbaby . . .And suddenly you are calling your child Bisco for years!

I think it depends on the nickname as well.

So for example, if you have a baby called Jessica and the parents call her Jess, I think they’d be a little weird to be upset if a grandparent sometimes said Jessie.
But if you have a baby called Elizabeth and the parents call her Lizzie, it would be weird for a grandparent to decide to use Beth.

If they are new parents (in your OP) who have chosen eg Robert but you call him
Bobby, yet other family members decide to call him Bertie, I think that’s bizarre.

When they are older and at school/with friends then other names emerge but deliberately using different names than the parents for a new baby is just dickish.

If a child is called Beth by her parents , you should call her that too. It's not fair to use a different name even if that name is on her birth certificate. Teachers will say Beth.

I agree completely. My relative was batshit. As they got to know me, the 'diminutive' was dropped.

I think they had a point in that the name they called me was nicer than my given name, but to do it because they didn't like my parents' choice was weird and probably a control thing.

A friend's DD has a name with two obvious shortenings (e.g. Matilda/Tilly/Tilda) and when someone whether she'd be Tilly or Tilda they were corrected to the full name. The parents decided on another 'diminutive' and the baby was soon Molly and has been known as Molly ever since and is only Matilda on her BC.

(The names are examples, not the actual ones.)

The parents are the ones who chose the name. They know better than anyone else what their baby’s name is and what their baby should be called. They have full say until the baby is old enough to express an opinion. The other family members are free to have their own children and call them what they’d like. You do not get to essentially rename someone else’s baby (as diminutives often become permanent).

They’ll never admit it, but I feel like some people do this on purpose as some sort of bizarre control thing or to be petty. It’s like once they find out that the parents don’t like a certain diminutive (or don’t want the name to be shortened at all), they’ll suddenly insist on shortening the child’s name constantly. It’s almost like they have the attitude of I’m going to call your child this because I know that it irritates you, and there’s nothing you can do about it. It’s obnoxious behaviour and very childish, honestly.

Never make it obvious that you don’t like a certain diminutive of your child’s name or don’t want it to be shortened.

It was just a hypothetical eg.

It's not. If the parents don't want it used then that should be respected.

It's more affectionate too. But some families just aren't into affectionate-sounding names, I get that.

It's bloody awful and is longer than Angus.

If DM or DMIL called my baby Gussie they'd be told in no uncertain terms what to do with that idea.

Well some people would be like that, it's true.

I know a Christopher whose parents called him Gopher and his grandparents called him Kipper (both interpretations or variants of how he tried to say his name at about 18 months).

Gopher stuck and his mates still call him that, but only his Grandparents ever called him Kipper. He loved them having a special name for him and it kind of marked out the relationship with them. They used to buy him plush fish and birthday cards with kippers, while his parents did the same with Gophers. No-one minded too much!

But saying "well we don't like Lizzie so if you don't mind we're going to call her Beth" would be out of line I think.

I disagree. My parents named me. They said not to shorten it. One relative didn't like my name and called me a diminutive of sorts. (The diminutive is OK but wasn't and isn't 'me' and it was something like calling an Angela Anna)

Only one of my cousins goes by a diminutive and it's one used from birth and is something like Alex. The relative obviously disliked my name.

If DM or DMIL called my baby Gussie they'd be told in no uncertain terms what to do with that idea.