Primo Levi managed to use Latin to communicate with a Polish priest with whom he didn't have any other language in common.
> After World War II the Italian writer and Auschwitz survivor Primo Levi was walking back to Italy from Poland. Tired and starving, he met a priest, who spoke neither French, or German, or Italian. Ubi est mensa pauperorum? Levi asked. Where is the table for paupers?
(I have also used Latin to communicate with a priest with whom I didn't share any other language, although it was less surprising because it was at a spoken Latin event.)
Recently Liliana Segre, an Italian Auschwitz survivor and senator for life, was heavily criticized by (some) Italian politicians for proposing that the Parliament should set up a committee to investigate racism, anti-semitism and hate speech.
Since some critics were saying that she did not "love her country" (or something to that effect), she replied by recalling a brief conversation she had at Auschwitz with a prisoner from Eastern Europe. Both were teenagers and they were only able to communicate thanks to Latin. Patria mia pulchra est; Familia mea dulcis est; Cor meum et anima mea tristes sunt. (My motherland is beautiful; My family is sweet; My heart and soul are sad). She was still attached to the same country that sent her there.
> After World War II the Italian writer and Auschwitz survivor Primo Levi was walking back to Italy from Poland. Tired and starving, he met a priest, who spoke neither French, or German, or Italian. Ubi est mensa pauperorum? Levi asked. Where is the table for paupers?
https://www.latimes.com/archives/la-xpm-2002-jul-21-bk-chamb...
(I have also used Latin to communicate with a priest with whom I didn't share any other language, although it was less surprising because it was at a spoken Latin event.)