“For then I will make the peoples pure of speech, So that they all invoke Hashem by name And serve Him with one accord” ZEPHANIAH 3:9 (The Israel Bible™)
Zephaniah describes how in the future, all the nations of the world will have ‘pure speech,’ safa b’rurah (שפה ברורה). Many commentators maintain that the pure speech that Zephaniah promises is the language of Hebrew, and that in future times the whole world will begin to learn Hebrew. Biblical Hebrew is known as lashon hakodesh (לשון הקודש), ‘the holy language’. Since the Jewish people are a holy people, they speak the holy language, and since it is holy and pure, it contains no vulgar or shameful words. This verse is another incredible example of an obscure prophecy that has come to prominent fruition in our generation, as millions of people all over the world, both Jews and gentiles, are learning Hebrew in order to speak lashon hakodesh.