Ghostspeak amulet

The Ghostspeak amulet or Amulet of Ghostspeak is obtained during The Restless Ghost quest, from Father Uhrney in the Lumbridge Swamp. If the amulet has been lost, a player can always speak with Father Uhrney to receive another one. When worn, it can be used to talk with some ghosts. If not worn, the player will only hear "woooo wooo wooooo woooo" when attempting to speak with a ghost.

Quests
After The Restless Ghost, the Amulet of Ghostspeak is required for the following quests: Animal Magnetism, Do No Evil, Nature Spirit, Ghosts Ahoy, Making History, Creature of Fenkenstrain, Smoking Kills, A Fairy Tale Part I, Cabin Fever, Spirit of Summer and Summer's End (only if Ghosts Ahoy has not been completed).

Miscellaneous uses
The Amulet of Ghostspeak is also necessary for shopping in Port Phasmatys, or speaking to Metarialus, the ghostly brewer in the basement of the Port Phasmatys pub, to receive brewing instructions or trade for ale yeast. It is also needed to obtain Ghostly robes in the Ghostly robes miniquest. Contrary to popular belief, Amulet of Ghostspeak is not needed to enter Port Phasmatys.

In addition, the amulet allows players to speak to the ghostly musicians, as well as the ghosts in Melzar's Maze on the second floor. It is assumed that the ghosts in the maze are killed survivors of Elvarg's destruction, who were stationed at Rimmington; their conversations and locations, especially the comments about a dragon, seem to coincide with this.

Under typical circumstances a player can only get one Ghostspeak amulet as Father Uhrney will not give an amulet to player who has one in their possession. More than one can be obtained, however, by using the drop trick, though Uhrney will be able to detect amulets (including cramulets) in the player's bank, and refuse to give more if any exist there. (Some players obtain multiple amulets for the convenience of having them in the bank in case they die and lose one.)

Enchanted version
During the Ghosts Ahoy quest, the Old Crone will enchant it so that Necrovarus can be controlled, after you bring her the robes, book, and translation manual she asks for. It takes on a green glow for the remainder of the quest.

The old crone no longer enchants the amulets after the quest, however it is possible to keep some by doing drop trick whenever you do something with the amulet during the quest.

Trivia

 * You do not need the amulet of ghostspeak to understand what some ghosts say (for example Zabeth Corvid).
 * Getting a new Ghostspeak Amulet from Father Urhney is an Easy Lumbridge/Draynor task.
 * After completion of the Morytania hard task set, you will be able to understand all ghosts without the Amulet of Ghostspeak, the Dead monkey from the Do No Evil quest is the sole exception to this.