There are many kinds of questions in Lojban: full explanations appear in Section 19.5 and in various other chapters throughout the book. In this chapter, we will introduce three kinds: sumti questions, selbri questions, and yes/no questions.
The cmavo ma is used to create a sumti question: it indicates that the speaker wishes to know the sumti which should be placed at the location of the ma to make the bridi true. It can be translated as “Who?” or “What?” in most cases, but also serves for “When?”, “Where?”, and “Why?” when used in sumti places that express time, location, or cause. For example:
The listener can reply by simply stating a sumti:
Like ko, ma can occur in any position where a sumti is allowed, not just in the first position:
A ma can also appear in multiple sumti positions in one sentence, in effect asking several questions at once.
The two separate ma positions ask two separate questions, and can therefore be answered with different values in each sumti place.
The cmavo mo is the selbri analogue of ma. It asks the respondent to provide a selbri that would be a true relation if inserted in place of the mo:
A mo may be used anywhere a brivla or other selbri might. Keep this in mind for later examples. Unfortunately, by itself, mo is a very non-specific question. The response to the question in Example 2.68 could be:
or:
Clearly, mo requires some cooperation between the speaker and the respondent to ensure that the right question is being answered. If context doesn't make the question specific enough, the speaker must ask the question more specifically using a more complex construction such as a tanru (see Section 2.9).
It is perfectly permissible for the respondent to fill in other unspecified places in responding to a mo question. Thus, the respondent in Example 2.70 could have also specified an audience, a topic, and/or a language in the response.
Finally, we must consider questions that can be answered “Yes” or “No”, such as
Like all yes-or-no questions in English, Example 2.71 may be reformulated as
In Lojban we have a word that asks precisely that question in precisely the same way. The cmavo xu, when placed in front of a bridi, asks whether that bridi is true as stated. So
is the Lojban translation of Example 2.71.
The answer “Yes” may be given by simply restating the bridi without the xu question word. Lojban has a shorthand for doing this with the word go'i, mentioned in Section 2.11. Instead of a negative answer, the bridi may be restated in such a way as to make it true. If this can be done by substituting sumti, it may be done with go'i as well. For example:
can be answered with
or
(Note that do to the questioner is mi to the respondent.)
or
or
A general negative answer may be given by na go'i. na may be placed before any selbri (but after the cu). It is equivalent to stating “It is not true that ...” before the bridi. It does not imply that anything else is true or untrue, only that that specific bridi is not true. More details on negative statements are available in Chapter 15.