I agree with pp that you need to tell children when they are being boring or annoying. There's no need to be harsh but if you don't teach them this, how on earth will they learn it?
Every year I am shocked to find children in my class (I have taught the full ks2 range) who do not see ANY time when they should not be talking and have no concept that it is rude to interrupt. It is always at top volume.
Me: now, everyone just be quite for a second and decide which one you're voting for
Child: I'm voting for....
Me: put your hand up if you have a question
Child: where do we...
Me: we need to be silent in the school corridors
Child: Mrs wellthen...
Me: does anyone not have their work?
Child: I've got mine
Me: once upon a time...
Child: James has got BLUTAC!!!
Some children speak during inputs, story time, silent thinking time, walking to assembly, while another child is speaking. They don't whisper, as all children (and many adults!) do when they shouldn't be. They speak at full volume ABOVE the person speaking, in order to be heard.
How can they have so few social skills? (sn aside). It is because they are treated as their voice is the voice of God and must always be heard.
And it isn't just some. I have this every year. As you can probably tell from this post, I have two or three this year!