Vocative phrases are not sumti, but are explained in this chapter because their syntax is very similar to that of sumti. Grammatically, a vocative phrase is one of the so-called “free modifiers” of Lojban, along with subscripts, parentheses, and various other constructs explained in Chapter 19. They can be placed after many, but not all, constructions of the grammar: in general, after any elidable terminator (which, however, must not then be elided!), at the beginnings and ends of sentences, and in many other places.
The purpose of a vocative phrase is to indicate who is being addressed, or to indicate to that person that he or she ought to be listening. A vocative phrase begins with a cmavo of selma'o COI or DOI, all of which are explained in more detail in Chapter 13. Sometimes that is all there is to the phrase:
11.1) coi
[greetings]
Hello.
11.2) je'e
[acknowledgement]
Uh-huh.
Roger!
In these cases, the person being addressed is obvious from the context. However, a vocative word (more precisely, one or more cmavo of COI, possibly followed by “doi”, or else just “doi” by itself) can be followed by one of several kinds of phrases, all of which are intended to indicate the addressee. The most common case is a name:
11.3) coi. djan.
Hello, John.
A pause is required (for morphological reasons) between a member of COI and a name. You can use “doi” instead of a pause:
11.4) coi doi djan.
Hello, John.
means exactly the same thing and does not require a pause. Using “doi” by itself is like just saying someone’s name to attract his or her attention:
11.5) doi djan.
John!
In place of a name, a description may appear, lacking its descriptor, which is understood to be “le”:
11.6) coi xunre pastu nixli
Hello, (red-type-of dress)-type-of girl.
Hello, girl with the red dress!
The listener need not really be a “xunre pastu nixli”, as long as she understands herself correctly from the description. (Actually, only a bare selbri can appear; explicit quantifiers are forbidden in this form of vocative, so the implicit quantifiers “su'o le ro” are in effect.)
Finally, a complete sumti may be used, the most general case.
11.7) co'o la bab. .e la noras.
Goodbye, Bob and Nora.
Example 11.6 is thus the same as:
11.8) coi le xunre pastu nixli
Hello, the-one-described-as red-dress girl!
and Example 11.5 is the same as:
11.9) doi la djan.
The-one-named John!
Finally, the elidable terminator for vocative phrases is “do'u” (of selma'o DOhU), which is rarely needed except when a simple vocative word is being placed somewhere within a bridi. It may also be required when a vocative is placed between a sumti and its relative clause, or when there are a sequence of so-called “free modifiers” (vocatives, subscripts, utterance ordinals — see Chapter 18 — metalinguistic comments — see Chapter 19 — or reciprocals — see Chapter 19) which must be properly separated.
The meaning of a vocative phrase that is within a sentence is not affected by its position in the sentence: thus Example 11.10 and Example 11.11 mean the same thing:
11.10) doi djan. ko klama mi
John, come to me!
11.11) ko klama mi doi djan.
Come to me, John!
As usual for this chapter, the full syntax of vocative phrases has not been explained: relative clauses, discussed in Chapter 8, make for more possibilities.