Most animals can communicate about things in the
immediate environment only. A bird utters its danger cry only
when danger is present. It cannot give information about a
peril which is removed in time and place.
Human language can communicate about things that are
absent as easily as about things that are present. This
apparently rare phenomenon, known as displacement, does
occasionally appear in the animal world . but this ability is
limited for animal communication.
Human language can cope with any subject whatever,
and it does not matter how far away the topic of conversation
is in time and place.