DCs 3 and 21 months.
I often say 'Stop crying' - never shout it but say with a degree of firmness. It quite often works on 21 month yr old and then I'll get her x, y, z. TBH, never worked as well with 3 yr old but I still said it.
Never questioned it before til I had a paranoid moment and thought is it an awful thing to say - like, am I making them feel they can't/shouldn't cry/invalidating their feelings etc?!
I did get some odd looks today when 21 month old went ape sh1t over a toy some kid snatched off her and she was properly blubbing and I said quite lodly "STOP crying STOP crying Would you like me to get you another toy?" and the tears instantly stopped. But then it was like I'd scared her into stopping crying IYSWIM?
I'm often surprised by how well it works with 21 month old, but maybe others have a different phrase they use instead?!