"What was your walk like?"
Translation:Kia estis via promeno?
Many fluent Esperantists (me included) make the same error and use kiel in all cases, even when an answer with an adjective is expected. If you expect the answer to be something like bona, longa, elĉerpiga, interesa, plena je pluvo, enuiga etc., then you have to use Kia?. Think of kiel like a synonym for kiamaniere (in what manner).
WHICH, as I look at more sentences, seems to have to do with the part of speech. Kia seems to be used to describe nouns, and kiel for... well, everything else. So we have "Kia stultulo vi estas!" [NOUN] and "Kia estis via promeno?" [NOUN], but "Kiel vi fartas?" [VERB] and "Kiel verda estis mia valo." [ADJECTIVE].
In other words, the "answer" to kia is an adjective, and the answer to kiel is an adverb...
This theory is based only on observation, but so far it has held up for me...
I think that in "Kiel verda estis mia valo," "kiel" modifies verda, which would make it an adverb, although the whole thing -- "kiel verda" serves as an adjective?
Oh hey, look here, it does indeed always serve as an adverb: http://donh.best.vwh.net/Esperanto/correlatives.html
Two weirdnesses of English that I think impinge upon this seem, to me, to be lost in all this back-and-forth:
A strong cognitive barrier is set up by the concordance (or lack thereof) of two set phrases: How are you? → Kiel vi fartas? This use of “how is”, also found in constructions like “how’s your leg?”, “how’s the homework coming?”, etc., encompass a non-copulative verb of seeming (feeling, etc.) into the “how”. This is highly idiosyncratic but is such a basic part of English that L1 speakers don’t realize how strange it is.
English is somewhat sloppy with its use of adverbs versus adjectives in response to questions. Questions phrased like “How are you?” should “properly” be answered with an adverb (well, badly) but in colloquial usage are more frequently answered with an adjective (good, bad). We only tend to see the distinction at all when it’s divorced from the context: “Q: ‘How are you?’ A: ‘I’m good.’” comes across very differently (“glad to hear it!”) from an unprompted “I’m good!” (“oh, really? What did you do now?”)
These two factors conspire to make English speakers not realize that “How was your walk?” is not at all like, “How was your recipe developed?”