The inscription on the one ring is written in Elvish "Black Speech" the language of Mordor and in the film is said to read
One ring to rule them all
One ring to find them
One ring to bring them all
And in the darkness bind them...
In the book Gandalf tells the whole Verse from which these lines come from;
Three rings for the Elven-kings under the sky,
Seven for the Dwarf Lords in their halls of stone,
Nine for Mortal Men doomed to die,
One for the dark Lord on his dark throne,
In the Land of Mordor where the shadows lie.
One ring to rule them all one ring to find them,
One ring to bring them all,
And in the darkness bind them,
In the land of Mordor where the shadows lie.
One ring to rule them all
Hope that answered your Question...