What one language did the whole world share in Genesis 11:1?

Answer From The Annual Reading Schedule - Week 3 Notes For Genesis: My belief is that the whole world shared the language of Hebrew and that Hebrew is the original language of all humans. I have also read somewhere online there is a Jewish traditional belief that Ever (Eber) did not follow those in taking part in the building of the tower of Bavel (Babel) and so when the others had their language confused, the Hebrew language was retained by Ever. There is prophesy in Zephaniah 3:9 that may be pointing to all of us, one day, once again sharing the same language – a pure language – which I believe will be Hebrew again.