I recently heard the language of the Celestial Kingdom is Spanish. Is this true? Also will each kingdom have the same or a different language?
When Adam was placed on the earth he was given a language that was pure and undefiled. (See Pearl of Great Price, Moses 6:5-6).
5 And a book of remembrance was kept, in the which was recorded, in the language of Adam, for it was given unto as many as called upon God to write by the spirit of inspiration;
6 And by them their children were taught to read and write, having a language which was pure and undefiled.
The children of Adam spoke that pure language until the time of the Tower of Babel. At that time, because of the great wickedness of the people and in order to prevent them from pursuing their enterprise of building a tower that they had designed to reach to Heaven, the Lord confounded their language, so that they could not understand one another’s words.
There was one exception to that confounding of tongues. It can be found in the Book of Ether, one of the books of the Book of Mormon, wherein we learn that two families, those of Jared and his brother, Mohonri Moriancumer, and all their friends, were all granted the blessing of retaining, as their own, the pure and undefiled language given to Adam.
Interesting enough, as you study the Book of Mormon, you will find that this group was led to the New World where their descendants existed as a nation for a period of a thousand years. One of their later historians wrote a record of that civilization on plates of gold in the Adamic language. If translated into English it would occupy about 1000 pages of written text. However, the original text was written on only 24 plates of gold. So the written language of Adam was a very powerful writing form.
Now that should give you some idea of what languages are NOT the language of the Celestial Kingdom.