Distinguishing meanings of A/V + (으)ㄹ 줄 알았다

Question

Consider the sentence 그사람은/저는 운전할 줄 알았어요. I have heard that translated as "I/he/she know/knows how to drive". However, this explanation seems to translate it as "I thought I/he/she would drive".

How can I reconcile this meaning? And does it scale well to other tenses like 운전할 줄 알아요 or 운전할 줄 알 거예요.

Edit:

I may have actually arrived at my answer. I think 운전할 줄 알았어요 means "I thought I/he/she would drive" while 운전할 줄 알아요 means "I/he/she know(s) how to drive"; notice the difference in tense. It does, however, beg the question: how does one say "I thought he would drive" and "I think he will drive".

Answer 1

There is no way to distinguish which meaning it refers to except by guessing.

In addition, due to the fact quoted above, native Koreans tend not to use this grammar, but simply ㄹ 수 있다 or 어떻게 ... 는지 알았다 to express the meaning "to know how to..." during these few years.

Example: 한국어를 할 줄 아시나요? has been replaced by 한국어를 할 수 있으세요? and used by most natives in recent years.

Of course, Koreans still use this grammar, but usually when they try to mean "I thought ...".

Answer 2

As always, context matters. There are some cues:

1. "-줄 알다" as "can" or "have the ability to" is paired with future tense -ㄹ.

   저는 영어를 할 줄 알아요. = I know how to speak English.

   (X) 저는 영어를 하는 줄 알아요.

   (X) 저는 영어를 한 줄 알아요.

   On the other hand, present/past tense is possible for "think":

   비가 올 줄 알았다. = I thought it would rain.

   비가 오는 줄 알았다. = I thought it was raining.

   비가 온 줄 알았다. = I thought it had rained.

2. If "-줄 알다" means "[I/you/he/she/...] think that...", then it is usually in past tense ("I thought ..."), or the subject is not "I". In other words, this form is not used to mean "I think that...".

   비가 올 줄 알았다. = I thought it would rain.

   (??) 비가 올 줄 안다. (Cannot mean "I think it would rain.")

   (cf. 비가 올 것 같다. = I think it would rain.)

   그럴 줄 알았다. = I knew this would happen.

   Present tense is possible with other subjects, but I think in this case it usually means "think X even though it's not (likely) true":

   내가 그런다고 그만둘 줄 아니? = Do you think I would stop at this?

   저 고양이는 자기가 주인인 줄 안다. = That cat thinks it's the master.

3. Finally, note that 비가, 내가, 자기가 above are all using -이/가, instead of -은/는. This is because they are inside the subordinate clause:

   저 고양이는 [자기가 주인인 줄] 안다. = That cat thinks [it's the master].

So, to conclude:

그 사람은 운전할 줄 알아요. = He knows how to drive.

(저는) 그 사람이 운전할 줄 알았어요. = I thought he would drive.

So, the sentence in question, I think "그 사람은 운전할 줄 알았어요" is ambiguous, because it's a bit "equally unusual" either way:

1. If it means "can", then one would normally use "알아요", because "being able to drive" is normally not something you would put in past tense: if you could drive yesterday, you are still able to drive today. Note that "-줄 알아요" always means capability: is not used for being authorized to do something (as in "You can go home after you finish this").

2. If it means "to think", then it should normally be "그 사람이". However, one could think of a situation to use "-은" (with accent) to signify contrast:

   저는 걷는 게 편해서 걸어왔어요. 하지만 그 사람은 운전할 줄 알았어요. = I walked here because I like walking, but I thought he would drive.

Now, you might think this is all extremely complicated, but when you think about it, it's not much more complicated than deciding whether "He must be in the room." means "I'm sure he's in the room." or "I hereby order him to stay in the room." :)

Answer 3

To answer the new edit to your question: "how does one say "I thought he would drive" and "I think he will drive"."

I thought he would drive = 그가 운전 할 줄 알았어요. I think he will drive = 그가 운전 할 것 같아요.

Notice the difference in tense.

To your original question of how to not confuse the meaning of 그가 운전할 줄 알았어요, this can mean two things and needs to be inferred from the context. 1) I thought they would be driving. (expectation of an action) 2) They knew (past tense) how to drive. (doesn't provide information on whether or not they have now forgotten that skill) A more clear way of saying that they once knew, but now have forgotten, how to drive : 그는 운전할 줄 알았었어요 (notice the additional past tense)