So I work in a field where myself and my coworkers are involved in international partnerships, some of which are in the UK. A coworker of mine, who had very little understanding of British vernacular had the following in an e-mail exchange.
British Rep: "I look forward to finalizing our coordination efforts on this topic.
US Rep: "As we say in the military, 'Roger that'"
British Rep: "Your last statement does not, hilariously, translate well in British vernacular. I do however, understand your conveyance."
Given how almost every thread in this forum seemingly devolves into a discussion about language, I figured I'd post this here. I just found it amusing that a man who is deeply immersed in British culture never realized that "Roger that" meant something completely different in another country.
Maybe I knew this because I lived in the UK as a kid for several years (doubtful since we left when I was 4). Maybe I knew it because I travel there on a regular basis (doubtful as I'm pretty sure I knew it prior to starting my current profession). If I had to guess, I learned this by watching pop culture movies sometime in the last 20 years.
So let this be a lesson that before you use a colloquialism in your own language, make sure you understand the vernacular (and its colloquialisms) of the recipient.