UKCasual

I'm from the USA, yet I prefer to spell gray as grey, and sometimes, depending on programming context, color as colour.

A few of my friends and I do the same with a few words, especially colour. But, it's to do with the books we read as kids because internet access wasn't common yet

I watch a lot of Matt Parker and numberphile videos and on occasion find myself saying maths instead of math. You tend to pick up the habit and speech patterns of those in your social circles. That includes online and video interactions. I remember reading about some parents whose kid watched so much Peppa pig that the american kid was developing a british accent.