The largest deployment of U.S. Marines to Australia is underway.

About 1,700 Marines began arriving in Darwin, Australia, in April for training and exercises, and their ranks eventually are expected to grow to 2,500.

And despite being in its eighth iteration of Marine Rotational Force–Darwin — not to mention speaking the same language — Australian troops have been ordered to avoid using slang around American counterparts.

“Imagine an American asking an Aussie soldier if they can see the enemy approaching and they respond with the classic local phrase of ‘nah, yeah’. The Yank would have no clue if they meant yes or no, which is understandable for someone who doesn’t get our slang," the site LADbible said.

It seems that communication should be crystal clear if you’re operating military equipment. Here’s what Australian Air Force Group Captain Stewart Dowrie, from Robertson Barracks, explained to news site 10 Daily:

“We have lost in translation moments more than you would realise.”

“The time to figure that out is not on the battlefield when the bullets are flying.”

“Classic phrase ‘lucked out’ ― for some people it means you get lucky, for others it didn’t happen."

“So you start using colloquialisms and all of a sudden you have complete misunderstandings about whether something is going to happen.”

Football, anyone?