This is possible because language is not the only symbolic means of communication. In order to prove that chimpanzees and gorillas are capable of language, and not simply a different kind of symbolic communication system, they must learn a sign language with the basic characteristics of human language.
Definition of Halloween. : October 31 observed especially with dressing up in disguise, trick-or-treating, and displaying jack-o'-lanterns during the evening.
Every October 31, both children and adults slip into the night as ghouls and goblins, princesses and pirates. Many Americans celebrate the traditions of Halloween by dressing in costumes and telling tales of witches and ghosts. Pumpkins are carved into glowering jack-o'-lanterns.