Well, on one hand, Jyn doesn't say a word. In any language. She does, however, dissolve into laughter, luckily stifled from the dress stuck over her head so she doesn't wake up Sofia.

Unluckily, when Jyn tries to help Cassian along in getting the dress finally over her head, the squirming and laughter makes her knee him in the stomach. Which prompts her to dissolve into more laughter because of course this is how it's going to go for them.

Of course. "'m sorry!"