The book of Ether in the Book of Mormon comprises 31 pages.  It was placed there by Moroni.  He stated that it was his abridgment (Moroni 1:1) of the 24 gold plates found by the people of king Limhi.  In the second-to-last verse of the abridgment he says, "and the hundredth part I have not written."  (Ether 15:33).

That is an astonishing statement.  If 31 English pages are less than a hundredth part of the full record, the full record, if we had it, would fill over 3,100 pages when translated into English.  Even more astonishing is that those 3,100 potential pages could come from only 24 gold plates.

Ether's engravings must have been very small, and he must have been writing in a very efficient language that used far fewer words than most other languages.

In Vanuatu I recall comparing the number of words required in Bislama and English for the sacrament prayer to be said over the bread.  Bislama required more words than the 91 words required in English.  The same prayer in Spanish requires 83 words, while Russian requires only 71.

Ether's language must have been far more efficient.

What language did he use?  Was Ether the author of all 24 plates, or were they a collection of the writings of many prophets?

When leaving Mesopotamia, Jared and his brother prayed that the Lord would not confound their language.  Their request was granted.  (Ether 1:35).  Up to that point all the world was speaking the same tongue.  That language was the Adamic tongue, the same language spoken by Adam and Eve.

Jared and his brother brought a record with them when they made their voyage to the promised land.  (Ether 8:9).  The daughter of another Jared (she being the seventh generation from the original Jared) was able to read the record.  She, and the rest of the Jaredites down to Ether, were apparently still speaking the Adamic tongue.  The 24 gold plates were likely written in the Adamic language.

Was Ether the author of everything on the 24 plates?  Possibly, but not necessarily.  Perhaps he had the plates handed to him by a previous prophet.  He either continued the record keeping, or perhaps made his own abridgment of other records that were available to him.

How we would love to have the full account!  How I would love to be able to understand how a potential 3,100 ages of English could be condensed to occupy just 24 gold plates!

This is fascinating to think about, but too little information is available to be able to come to conclusions.