It's from Return of the King. Annie Lennox sung it. It won an Oscar.
The end credits always have a song that is sung in English. In Fellowship of the Ring it was May It Be by Enya. Two Towers was Gollum's Song sung by Emiliana Torrini.
The Hobbit films. An Unexpected Journey: The Song of the Lonely Mountain by Neil Finn. Desolation of Smaug: I See Fire by Ed Sheeran. Battle of Five Armies: The Last Goodbye by Billy Boyd.
There are plenty of songs through the soundtracks for the LotR films that have lyrics. A lot in Elvish but quite a few in English.
Allow me to introduce you to the wonder that is
A Magpie's Nest. All the lyrics from both the theatrical and the extended editions of the LotR films are on there, along with time stamps of where they appear in either the OST or on the Complete Recordings. She has said that she won't be doing the Hobbit films soundtracks and I don't know if anybody has started something similar for the Hobbit films because it is a mammoth task.
Anyway, if you go to source songs and poems on there you will find the lyrics to all the songs in the LotR films.