but I'm one of the parties involved. And it's about the age-old question for students of Korean: "How can you tell the difference between verbs and adjectives in Korean?"
Well, the short version of the answer is that "it ain't easy".
Now, there are people who say that the distinction is clear. I, on the other hand, think that it's not as clear, even though the pedagogical tradition is to say that there are "verbs vs. adjectives". My view at this point basically concurs with those who say that Korean has two types of verbs (i.e. action and descriptive verbs) rather than a verb vs. adjective distinction.
No matter - a distinction's a distinction, right?
Well, yes, but it's not the same type of distinction.
Let me begin by using a language we all know very well - English. And let's start with a couple of easy examples of adjectives and verbs.
Verbs:
The boy sits.
The boy ate some rice.
Adjectives:
The boy is good.
The boy was fast.
Now, with the verbs, we notice one main thing: they can take tense (runs, ate). As for the adjectives, they cannot 1) occur by themselves - they must follow a copular verb (i.e. 'to be'); and 2) take tense marking - the copular verb takes it.
Let's take a look at Korean.
그 남자는 앉다. 'The boy sits.'
그 남자는 밥을 먹었다. 'The boy ate rice.'
그 남자는 좋다. 'The boy is good.'
그 남자는 빨랐다. 'The boy was fast.'
Now, notice that unlike English, the Korean 빠르다 may take tense marking directly, as we can say 빨랐다 with the -었/-았/-였 past tense suffix.
Some of you might be thinking at this point, "This is Korean, not English - this is like comparing apples to oranges." That's exactly my point - we must evaluate Korean on its own terms, rather than impose categories that just happen to exist in other languages. And so far, the evidence shows that there is no formal/structural distinction between 동작동사 ("verbs") and 상태동사 ("adjectives"/"descriptive verbs").
There is, however, a context where a distinction may be noticed - but it's not nearly as obvious as it is in English. This is when these forms modify nouns.
For the 동작동사, we have the following:
앉는 남자 'The sitting boy'
김치를 먹는 남자 'The boy who eats kimchi'
밥을 먹은 남자 'The boy who ate rice'
And for 상태동사, we have the following:
좋은 남자 'The good boy'
싼 밥 'cheap rice'
빨은 남자 'The fast boy'
Notice we can't say the following:
*싸는 밥 'the currently cheap rice'
(But can you say ?좋을 남자 'the boy who will be good'?)
So the difference between 동작동사 and 상태동사 is that in their noun-modifying forms, the 상태동사 cannot take the present tense -는 (as well as the questionability of the "future" -을/-ㄹ suffixes), while 동작동사 can.
But notice the one common thread between these two types of predicates: the -은 suffix. They both indicate something that has an established presence for the speaker: for 동작동사 marked with this noun-modifying suffix, these are activities that have already taken place (i.e. have been realized), while 상태동사 marked with the suffix are simply establishing an inherent, realized quality.
Going back to English, we see that the verb vs. adjective distinction is much clearer. For adjectives, we can just put them before a suitable noun unaltered, and they're fine:
The good boy
The fast boy
The cheap rice
However, for verbs, this would result in extreme ungrammaticality:
*The sit boy
*The ate rice boy
*The run boy
We cannot say the latter sentences because they need either extra marking (i.e. tense, e.g. the sitting boy, the running boy), or they need to be altered syntactically to be grammatical, e.g. the boy who sits, the boy who ate rice, and so on.
What I'm trying to say here is that it isn't clear whether 상태동사 are best described as adjectives as English speakers know them. Just because these capture states and qualities rather than actions does not make them automatically "adjectives" - they have to be clearly distinguishable when they are used in sentences. In this regard, I see 상태동사 as being another type of verb rather than a completely different word category.
But if you disagree, please let me know. Just be sure: don't just rely on what the "semantics" (that is, the definition or meanings) say - you really should provide some grammatical evidence (e.g. evidence [or lack thereof] of conjugation, and so on).
I hope this sparks some discussion.
