The word pun that Jesus makes in Matthew 16:18 in Greek (using similar words for “Peter” and “rock”: πετρος and πετρα) is lost in most languages (such as in English) but is naturally preserved in some languages, such as French (Pierre and pierre), Portuguese (Pedro and pedra), Italian (Pietro and pietra), Latin (Petrus and petram), Modern Greek (Πέτρος and πέτρα), and — to a lesser degree — in Spanish (Pedro and piedra) and in Romanian (Petru and piatră).
Despite the similarity between the words in those languages, readers might not automatically catch the word play, as Carlo Buzzetti (in The Bible Translator 1983, p. 308ff.) explains for Italian (click here to read more)
“In many languages it is not possible to repeat the same word, because the equivalent of Petros has become a personal name, while the equivalent of petra is a common noun, the gender of which may be different from that of the equivalent of Petros. The Italian linguistic situation seems at first sight to be very similar to the Greek: to translate Petros—petra we can use Pietro—pietra. But unfortunately this conveys a different meaning to the average Italian reader: first, because Pietro is now not a new nickname, but a common traditional personal name; and second, because pietra is a feminine noun similar in form to Pietro, but carrying no suggestion that the two have the same meaning. Indeed, Pietro, like ‘Peter’ and most personal names, carries no meaning at all for the average reader or speaker.
“The common language translators felt that it was possible to make the identification between Petros and petra explicit, and at the same time exploit the similarity between the two words. We thus translated: tu sei Pietro e su di te, come su una pietra, io costruirò la mia comunità [in the original Common Language Version: Chiesa] (‘you are Peter and on you, as on a rock, I will build my community [originally: ‘Church’]. Our te (‘you’) connected Pietro and pietra. while our come (‘as’) expressed the fact that the connection was based on an image. In this way we suggested the meaning of Pietro.”
Like the Peshitta translation in Syriac Aramaic (Classical Syriac) with the term ܟܹܐܦܵܐ (kēpā), the Neo-Aramaic languages of Assyrian and Chaldean use terms for both “Peter” and “rock” (and “Cephas”) that are identical (ܟܹܐܦܵܐ and كِيپَا, both pronounced kēpā) so the word pun is preserved in those translations as well. (Source: Ken Bunge)
See also Cephas.