It may be that Jonah made his proclamation in his native Hebrew and used an interpreter to relate it to the Ninevites.
ويُحتمل ايضا انه تكلم بالعبرانية ،‏ لغته الام ،‏ واستعان بشخص آخر ليترجم كلامه الى اهل نينوى .‏