Is "what" in 1 a relative pronoun or an interrogative? 2's "what" is definitely a relative pronoun, but 1's "what" seems to have dual opinions of native speakers.
1. It depends on what it is.
2. I had what I ordered.
This is an excerpt I found on the Internet, but I forgot where it's from. This and many Korean grammarians say so, confusing me.
s6: The girl who came yesterday is my niece. Relative.
s7: I can guess what Sally keeps in this box. Interrogative.
s8: Does Tom know which hat Mary likes? Interrogative.
s9: Where did Ann meet the girl who came yesterday? Relative.
s10: Does Tom know which Mary likes? Interrogative.
s11: Does Ann know who came yesterday? Interrogative.
s12: Do you know what Sally keeps in this box? Interrogative.
1. In particular, all these sentences that talk about knowing or guessing the answer to some question use interrogatives.
When "what Sally keeps in this box" refers to the particular thing(s) that she keeps in this box, what is relative; when "what Sally keeps in this box" refers to whether what she keeps in this box is x or y, then what is interrogative.
I don't know what you know. Two answers, depending on the meaning:
I don't know the same thing(s) that you know. -> Relative.
I don't know whether you know x or whether you know y. -> Interrogative.
I think an interrogative either asks (or exclaims) or can be explained with a whether or series of whethers.
Last edited by keannu; 30-Jun-2013 at 08:50.
OK, maybe. I read it as "It depends on that [thing] which it is."
But I can see how some might call it interrogative.
Retrospecting your and 5j's opinions on this issue of telling interrogative or relative pronoun, back then, I firmly believed that any sentence without question mark should have only a relative pronoun, not an interrogative. But I've always had this excerpt's opinion in mind as well. And thinking about it deeply, I reached the conclusion that it could all depend on the speaker's intention and the context like the following, but I'm not sure. If I'm mistaken, please correct me.
1. She has quite the knowledge of psychology, but I don't know what she knows => Relative pronoun intended, "what" refers to "the thing that or the knowledge of psychology'
2. It's not clear whether she knows psychology or history well, so I don't know what she knows. => Interrogative intended. "what" refers to which thing or which area.
I can understand your confusion.
Please look at the sentence below.
"I don't understand what she said."
1. If the 'what' is an "interrogative pronoun", I think the sentence is called an "indirect question".
"I don't understand." + "What did she say?" = "I don't understand what she said."
2. If the 'what' is a "relative pronoun", I think the sentence can be interpreted as follows:
"I don't understand what she said." = "I don't understand the thing(s) that she said.
They convey the same message, so it doesn't really matter which part of speech the 'what' is, I guess.
I'm not a grammarian, so I might be wrong.
But this is what I've been teaching to my students.
Your grasp of the theory is sound, but your application of it somewhat less so.
The verb 'understand' could not be used in combination with an interrogative 'what'. Your first example should therefore be amended to
I don't know what she said.
Naturally, however, collocation with other interrogatives is possible, e.g. 'why' in
I don't understand why she said it.