If you want to try this yourself, Dana from Made has a great tutorial on Freezer Paper Stenciling.
I chose the Irish Gaelic phrase "Dia Libh" meaning "God with You." The font for the green shirt is Livingstone (downloaded from dafont.com). I used Sherwood (also downloaded from dafont.com) for the white shirt. I printed out the two phrases and then traced them onto the freezer paper. After cutting the design out with an exacto knife, I ironed the design onto the shirt and painted it using Tulip's Glacier White Matte soft fabric paint. I think I did 2-3 coats.
Until then... dia libh.