Then it is not dry outside. The Easter bunny is coming to hide Easter eggs. To a child, this sentence may indicate that a rabbit lays eggs. Both speaker and listener know that John is indeed seeing Mary, who was in a scandal that separated Mary and Dan. Someone else hearing the statement would totally miss the incriminating information.
Meaning is provided solely by the language community in question.
A person s collection of words become that person s lexicon . The number is unknown to anyone including each individual person. An idiolect is the individualized collection of words each person uses.