Who can understand this joke?

This is mocking the incorrect English accent of China people and mistaking SUPPLIES for a surprise, because people in China usually pronounce R as L. 。

The foreman asked the Italians to sweep the floor and the Irish to shovel the sand, but they didn't do it, because the China people didn't provide them with tools, and the people disappeared.

Here the foreman put China people in charge of supplies, and China people thought he was in charge of surprise attack, so they hid. When the foreman came, he jumped out to scare him.

Do you understand?