In Swedish the word "Särskrivning" describes the incorrect splitting apart of compound words into individual words and the resulting change in meaning. An English example I can think of: groundhog vs. ground hog. The former is an animal, the latter a tasty meal when cooked.
Is there an equivalent English word or phrase for this concept?
No, there is not an equivalent word since split compound words is the norm in English.
The compound-word-splitting is a hassle in Swedish because all nouns are either one word (rektor - principal), a hyphenated compound word (e-post - e-mail) or a compounded word (sjuksköterska - nurse).
The last example is a Swedish compound of sjuk (sick) and sköterska (carer). As one word it means nurse (a carer of the sick) but if you split it into two it means a sick carer.
In Swedish you can create new word by compounding them to change their meanings. However, splitting compounded words into smaller pieces can change their meaning or, in most cases, make them loose their meaning completely. E.g. a lorry truck driver would just be written as one compounded word in Swedish: lastbilsförare. Splitting last, bil(s) and förare into three pieces would not make any sense; they still have their separate meanings but it would be like listing words without any connection between them. It’s like someone would write “I’m a lorry, truck, driver” – you would probably get what they mean but it would be annoying reading texts like that. Or, like in the example above; is the person in question a carer of the sick (nurse) or a sick carer? Either that person stated their profession or their health status and profession, however, you can't always be sure if it's as the text says or a spelling mistake with some compounded words when they are split up.
The 's' in parentheses is put between some sounds in Swedish to make the compounded words flow better. This is known as "foge-s" (a binding letter s) in Swedish.
There's a thing called metanalysis which is similar. "An orange" should really be "a norange", from Spanish naranja.
Now while looking up the exact word I found "hamburger". Ham doesn't mean cured pork and burger doesn't mean "flat round thing" in this context; they allegedly originated in Hamburg, the German city. So you could consider "chicken burger" to be close (and a culinary abomination to boot).
P.S. It might be an urban myth, but there was supposed to be a company that made writing equipment, called "Pen Island". Their website implied something quite different...
I suspect the closest word or phrase that exists in English would be misnomer, on the grounds that using a "compound" word as if it were separable with the same meaning would be an error.
For example, calling a pig laying on the ground a "groundhog" would be a misnomer. Similarly, calling the season-predicting rodent a "ground hog" would also be one. They are separate words/phrases and attempting to interchange them on apparent similarity is a misnomer.
However, I am not aware of any word or phrase that would also convey that implicit similarity.
