The following cmavo is discussed in this section:
kau UI indirect question marker
There is an alternative type of sentence involving “du'u” and a selbri expressing a propositional attitude. In addition to sentences like
8.1) I know that John went to the store.we can also say things like
8.2) I know who went to the store.This form is called an “indirect question” in English because the embedded English sentence is a question: “Who went to the store?” A person who says Example 8.2 is claiming to know the answer to this question. Indirect questions can occur with many other English verbs as well: I can wonder, or doubt, or see, or hear, as well as know who went to the store.
To express indirect questions in Lojban, we use a “le du'u” abstraction, but rather than using a question word like “who” (“ma” in Lojban), we use any word that will fit grammatically and mark it with the suffix particle “kau”. This cmavo belongs to selma'o UI, so grammatically it can appear anywhere. The simplest Lojban translation of Example 8.2 is therefore:
8.3) mi djuno le du'u
makau pu klama le zarci
I know the predication-of
X [indirect question] [past] going to the store.
In Example 8.3, we have chosen to use “ma” as the word marked by “kau”. In fact, any other sumti would have done as well: “zo'e” or “da” or even “la djan.”. Using “la djan.” would suggest that it was John who I knew had gone to the store, however:
8.4) mi djuno le du'u
la djan. kau pu
klama le zarci
I know the predication-of/fact-that
John [indirect question] [past]
going to the store.
I know who went to the store, namely John.
I know that it was John who went to the store.
Using one of the indefinite pro-sumti such as “ma”, “zo'e”, or “da” does not suggest any particular value.
Why does Lojban require the “kau” marker, rather than using “ma” as English and Chinese and many other languages do? Because “ma” always signals a direct question, and so
8.5) mi djuno le du'u
ma pu klama le zarci
I know the predication-of
[what sumti?] [past] goes-to the store
means
8.6) Who is it that I know goes to the store?It is actually not necessary to use “le du'u” and “kau” at all if the indirect question involves a sumti; there is generally a paraphrase of the type:
8.7) mi djuno fi le pu klama be le zarci
I know about the [past] goer to-the store.
I know something about the one who went to the store (namely, his identity).
because the x3 place of “djuno” is the subject of knowledge, as opposed to the fact that is known. But when the questioned point is not a sumti, but (say) a logical connection, then there is no good alternative to “kau”:
8.8) mi ba zgana le du'u
la djan. jikau la djordj.
cu zvati le panka
I [future] observe the predication-of/fact-that
John [connective indirect question] George
is-at the park.
I will see whether John or George (or both)
is at the park.
In addition, Example 8.7 is only a loose paraphrase of Example 8.3, because it is left to the listener’s insight to realize that what is known about the goer-to-the-store is his identity rather than some other of his attributes.