DEIXIS

Some sentences of English are virtually impossible to understand if we don´t know who is speaking, about whom, where and when.
Expressions such as tomorrow and here are obvious examples of bits of language that we can only understand in terms of the speaker´s intended meaning. They are technically  know as deitic expressions, from the  Greek word DEIXIS, wich means pointing via language.

Kind of Deixis:

• Person Deixis: We use Deixis to point to things, (it, this, these) and people(him, them, those).
• Spatial Deixis: Words and phrases used to point to a location (her, there, near that).
• Temporal Deixis: Those used to point to a time(now, then, last week).

All these Deictic expressions have to be interpreted in terms of wich person, place or time the speaker has in mind.

People can actually use Deixis to have some fun. The bar owner who put up a big sign that reads "Free Beer Tomorrow" can always claim that you are just one day early for the free drink.