According to this article, Francis doesn't speak English particularly well, though he understands it.
“What has always caused the most problems for me has been English,
especially the phonetics.” The reason, he said, is because he’s “tone
However, he's proficient in Italian and prefers to use it in public duties.
Benedict and Francis share ...
Although the line does not appear in the script, it does offer some insight.
Basically, she's aware that the dish is unappetising and is sympathising with Francis for having to eat it.
A covered plate is placed before Bergoglio.
He just prefers it that way. But he has arranged for you both to eat
the same meal. It’s a traditional ...