14. Vocatives and commands

You may call someone's attention to the fact that you are addressing them by using ``doi'' followed by their name. The sentence

14.1)    doi djan.
means ``Oh, John, I'm talking to you''. It also has the effect of setting the value of ``do''; ``do'' now refers to ``John'' until it is changed in some way in the conversation. Note that Example 14.1 is not a bridi, but it is a legitimate Lojban sentence nevertheless; it is known as a ``vocative phrase''.

Other cmavo can be used instead of ``doi'' in a vocative phrase, with a different significance. For example, the cmavo ``coi'' means ``hello'' and ``co'o'' means ``good-bye''. Either word may stand alone, they may follow one another, or either may be followed by a pause and a name. (Vocative phrases with ``doi'' do not need a pause before the name.)

14.2)    coi. djan.
    Hello, John.

14.3) co'o. djan.
    Good-bye, John.
Commands are expressed in Lojban by a simple variation of the main bridi structure. If you say
14.4)    do tavla
    -- =====
    You are-talking.
you are simply making a statement of fact. In order to issue a command in Lojban, substitute the word ``ko'' for ``do''. The bridi

14.5)    ko tavla
    -- =====
instructs the listener to do whatever is necessary to make Example 14.4 true; it means ``Talk!'' Other examples:
14.6)    ko sutra
    -- =====
    Be fast!

The ``ko'' need not be in the x1 place, but rather can occur anywhere a sumti is allowed, leading to possible Lojban commands that are very unlike English commands:

14.7)    mi tavla ko
    -- ===== --
    Be talked to by me
    Let me talk to you.

The cmavo ``ko'' can fill any appropriate sumti place, and can be used as often as is appropriate for the selbri:

14.8)    ko kurji ko
    -- ===== --
and

14.9)    ko ko kurji
    -- -- =====
both mean ``You take care of you'' and ``Be taken care of by you'', or to put it colloquially, ``Take care of yourself''.