Breakdown of Jesi li slučajno negdje zaboravio ključ?
biti
to be (sam, si, je)
li
question particle
ključ
key
zaboraviti
to forget
Questions & Answers about Jesi li slučajno negdje zaboravio ključ?
What does negdje mean here, and how does it fit with other location words?
Negdje means "somewhere". You form it by adding the prefix ne- (some-) to the question word gdje (where). If you wanted to say "everywhere," you would use svugdje, and for "nowhere" you would use the negative form nigdje.
Could slučajno mean something else here besides "accidentally"?
Yes! While it literally translates to "accidentally," Croatian speakers frequently use slučajno in questions to mean "by any chance." So a very natural way to read this sentence is: "Did you, by any chance, forget the key somewhere?"
Why are there two words separating Jesi li and zaboravio?
In Croatian, question words and short "grammar words" (clitics) like li must grab the first and second spots in a sentence. After that, word order is quite flexible. It's very common to place adverbs like slučajno negdje (accidentally somewhere) right before the main action verb (zaboravio) to build the context before stating the action.
Ključ (the key) is what was forgotten. Why hasn't its ending changed?
You're right that it needs to be in the accusative case because it's the direct object. However, ključ is a masculine noun that is inanimate (a thing, not a living being). For inanimate masculine nouns, the accusative form is exactly the same as the basic dictionary form.