Mine speaks Spanish, but has been learning English at school since last year, but so far she can understand if you ask her name, age, colors, numbers, a few animals, geometric figures, family members, knows how to say please and thank you, and kmows how to ask for permission to go potty.
I think that in a year and a half she will understand a lot more.
On the past cruise there was a CM from Argentina at the entrance, so we left dd in the OC, because said CM told us she would be there, and if dd needed anything she should just look for her, but they took the 3-4 group to the room behind the ship slide, and she needed something and couldn´t find the CM from Argentina in the room, and the CM in charge of the little ones wouldn´t let her out of the room so she could look for the Spanish speaking CM. I don´t think dd was crying or anything, I guess that if she had been, someone would have tried to understand her or page us, but the moment when I went to check on her and she saw me, she burst out crying and did not want to be left alone at OC again, so from then on, I would take her for some of the activities.
I am hoping that next cruise she will be lucky enough to have a spanish speaking CM in her group, or at least be better prepared herself to understand English.