Yes-no versus wh- questions

Questions can be divided into yes-no questions (also known as polar questions) and wh- questions (also known as constituent questions), according to the expected answer. As the name implies, the answer to a yes-no question is either 'yes' or 'no.' The answer to a wh- question is expressed by a constituent that corresponds to the wh- phrase in the question. Wh- phrases are so called because they generally begin with wh- in English (who, what, which, where, when, why). How counts as a wh- expression by virtue of its meaning, even though it doesn't begin with wh-. The term wh- phrase is standardly used even for languages other than English.

The distinction betwen yes-no questions and wh- questions is illustrated in (1) and (2).

(1)   Yes-no question   Has he called? { Yes, no. }
(2) a. Wh- question   Who just came in? The boy from next door.
b. Who(m) did you invite? All my friends.
c. When did she call? After dinner.
d. Why did he do that? Out of ignorance.
e. How did you fix it? With the right tool.

Direct versus indirect questions

Another distinction that can be drawn is between direct questions and indirect questions. Direct questions are main clauses, whereas indirect questions are part of a larger matrix sentence (possibly a question itself). Direct questions are generally used to elicit information. They are associated with characteristic intonation contours, which are represented in standard orthography by a question mark. Indirect questions are generally used to report about direct questions and are not associated with a special intonation.

The questions in (1) and (2) are all direct questions. The indirect questions corresponding to them are given in (3) and (4). Here and in what follows, indirect questions are enclosed in square brackets.

(3)   Indirect yes-no question   I can't remember [ { whether, if } he has called. ]
(4) a. Indirect wh- question   I can't remember [ who just came in. ]
b. I can't remember [ who(m) you invited. ]
c. I can't remember [ when she called. ]
d. I can't remember [ why he did that. ]
e. I can't remember [ how you fixed it. ]

(5) gives examples of various syntactic contexts in which indirect questions occur.

(5) a. Complement of adjective   I'm not sure [ whether they are coming. ]
b. Complement of preposition The question of [ whether they are coming ] remains unresolved.
c. Complement of verb She asked [ whether they are coming. ]
d. Subject [ Whether they are coming ] remains up in the air.

Finally, indirect questions can be finite or nonfinite, as shown in (6) and (7). Notice that if, in contrast to whether, requires finite complements.

(6) a. Indirect yes-no question, finite   They can't remember [ { whether, if } they should turn off the lights. ]
b. nonfinite   They can't remember [ whether to turn off the lights. ]
(7) a. Indirect wh- question, finite   They can't remember [ what they should pay attention to. ]
b. nonfinite   They can't remember [ what to pay attention to. ]

Information versus echo questions

Ordinarily, speakers use questions to elicit information, potentially initiating a discourse with them, as in (8).

(8) a.   How do you do?
b.   What's up?

But questions can also be used to signal a failure to understand the previous move in a conversation. The failure to understand can be genuine or feigned (calculated to express surprise, disapproval, outrage, and so on). Accordingly, we can distinguish between information questions and echo questions (also known as reprise questions); the latter two terms underline the response character of the second type of question. Echo questions can have the same syntactic form as information questions, but they are associated with a melody that is quite distinct from that of information questions. Speakers can also further mark the special discourse function of echo questions by giving them a special syntactic form in which the wh- phrase does not undergo wh- movement. The wh- phrase is said to remain in situ. (9) and (10) illustrates the two forms that echo questions can take.

(9) A.   Over break, I ended up visiting my (unintelligible) .
B.   Who did you end up visiting? (wh- movement)
  You ended up visiting who? (wh- in situ)
(10) A.   Her father burned all of her clothes.
B.   What did he do?! (wh- movement)
B.   He did what?! (wh- in situ)

The association of the wh- in situ form with the echo function is not universal. Some languages do not have wh- movement at all (see Chapter 13 for discussion), and some wh- movement languages allow wh- in situ questions to serve as either information questions or echo questions. This is illustrated for French in (11) (Engdahl 2006:104, (33)-(34)).

(11) a. A. 
Ton  fils, il lit   quoi?
your son,  he reads what
'What does your son read?'
(information question)
Des    bandes dessinées.
of-the comics
b. A.
Mon fils, il lit   [inaudible]
my  son,  he reads
'My son reads ...'
Il lit   quoi?
he reads what
'He reads what?'
(echo question)