The hazard
A lot of the safety on a job depends on messages getting through: the morning plan, a shouted warning, a hand signal to an operator, a tag on a switch, a label on a drum. On a crew that speaks more than one language, any of those messages can get lost without anyone noticing. A nod does not always mean someone understood. Clear communication is a safety control, just like a guard or a harness.
The action
Pick one stop word and one stop hand signal that the whole crew knows in both languages, like "Stop" and "Alto," and practice them. On crane work, the operator must obey a stop or emergency stop signal, no matter who gives it. Make it the crew's habit on every job: when anyone calls stop, everyone freezes until it is clear. (29 CFR 1926.1417(y))
ASK THE CREW
How can we check that someone understood the plan, not just nodded?
From the talk: Safety communication on mixed-language crews. Read it in full, free, with the questions and the sign-in sheet.