Probably any language that they want to speak in since they are God and they created all of the original languages. After the flood when the Human race was trying on their own works to reach God and Heaven by building their tower of Babel, which means confusion, then did God create all the other languages.” And the whole earth was of one language, and of one speech. And it came to pass, as they journeyed from the east, that they found a plain in the land of Shinar; and they dwelt there. And they said one to another, Go to, let us make brick, and burn them throughly. And they had brick for stone, and slime had they for morter. And they said, Go to, let us build us a city and a tower, whose top may reach unto heaven; and let us make us a name, lest we be scattered abroad upon the face of the whole earth. And the LORD came down to see the city and the tower, which the children of men builded. And the LORD said, Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do. Go to, let us go down, and there confound their language, that they may not understand one another’s speech. So the LORD scattered them abroad from thence upon the face of all the earth: and they left off to build the city. Therefore is the name of it called Babel; because the LORD did there confound the language of all the earth: and from thence did the LORD scatter them abroad upon the face of all the earth.” (Genesis 11:1-9 ).God then made all people to start speaking in different languages and they went off with their own groups who spoke the same languages to different areas of the world where God directed them to settle. And they left off to finish building the tower of Babel when God confused their tongues. God is Omniscient which means all knowing. They ( God, and Jesus, and the Holy Spirit ) can understand all the languages in the world and even read the minds of everyone in the world, and the people in Heaven and in Hell at the same time. Wow! That is pretty powerful! We have an Awesome God ! So what language will we all speak when Jesus comes back? The Bible says,”Therefore wait ye upon me, saith the LORD, until the day that I rise up to the prey: for my determination is to gather the nations, that I may assemble the kingdoms, to pour upon them mine indignation, even all my fierce anger: for all the earth shall be devoured with the fire of my jealousy. For then will I turn to the people a pure language, that they may all call upon the name of the LORD, to serve him with one consent.” (Zephaniah 3: 8,9 ). I think the “pure language” will possibly be Hebrew. Since Hebrew, is the language which the Old Testament was first written in, and God gave the Ten Commandments in So you might want to start learning some Hebrew to get a jump on things. However in the book of Acts when the Holy Spirit came upon the Disciples and they started speaking in different languages to witness to all the people in Jerusalem who had come from all different parts of the world, those languages were supernaturally given to the Disciples without ever studying them or learning them, so that will happen again when we get to heaven, we will get our new bodies, and a new name, and a new language. Shalom ma likeum, Ma likeum shalom. Which means, peace be unto you. Unto you be peace.