After writing my previous reply, I was reminded of what Noah prophesied about the eventual relationship of the three main ethnic groups with each other,
"Blessed be the LORD, the God of Shem!
May Canaan be the slave of Shem.
May God extend the territory of Japheth;
may Japheth live in the tents of Shem,
and may Canaan be his slave." Gen 9:26-27: NIV
It implies that everything will basically depend on Shem and that he will be the most powerful of the three - that the Bible actually states implicitly. He could therefore declare Hebrew as a world language. This is very hypothetical though. What is scriptural, is that the nations will have to come to Jerusalem to celebrate the Feast of Tabernacles. That will give them a brush with Hebrew, like even today with the yearly FOT the ICEJ hosts in Jerusalem where some Hebrew songs are sung.
Furthermore, the Kingdom will actually be on earth during the millennium of Messianic rule. It will no doubt have an effect on the amount of Hebrew that will be used.
It's interesting to note that Israel is today swarming with foreign workers, and many of for instance the Thais, Filipinos and Hispanics speak quite fluent Hebrew from just working among Israelis.
thank you brother? but i've question pls...how did you know that the language un heaven is hebrew? any Bible verses reference, please. thanks...God bless you. 
