expresso
It's not hard to say- Really.
Try it.
Espresso.
Now say, "Expresso."
Yeah... see the difference? One has an 's' and the other has a 'x.'
Starbucks serves espresso. It's delicious. Get used to saying it correctly. But then again, go ahead and say it whatever way you want. The barista will just have a good chuckle at your expense.