In media studies academic papers I see sometimes the term ストーリー is used and other times 物語 is used. I feel there might be a nuanced difference between the two. Could someone explain scenarios when something is one but not the other?
Story in English is a word that can refer to both the work/tale itself and its plot/content. When you say "the plot of this story", story refers to a work. When you say "the story of this movie", story refers to the plot.
In Japanese, both ストーリー and 物語 can refer to both a work itself and its plot. But there are nuances you have to consider.
- 物語 tends to refer to a work itself, and it's often a dramatic, long and/or old one (tale, legend...). It can also refer to the content of a work, but when it does, it functions more like drama rather than plot.
- ストーリー tends to refer to a plot. It can also refer to a work itself, but when it does, it's closer to (often short) episode.
For example, it's natural say この物語のストーリー referring to the plot of some dramatic work (novel, movie, etc.), but このストーリーの物語 sounds a bit puzzling to me.
Things like fairy tales, folklore and legends are almost certainly 物語, not ストーリー. On the other hand, customer stories you can find on business websites are not 物語 because it's short, modern and, um, businesslike.
When you visit the official website of a movie, you can find the ストーリー (or あらすじ) section. It would be rare, if ever, to see 物語 in this situation.
この映画のストーリーに感動しました and この映画の物語に感動しました are almost the same. 彼の演説にはストーリーがあった sounds to me like his speech was technically well-constructed, whereas 彼の演説には物語があった sounds to me like his speech was dramatic and heart-touching.
In terms of meaning, both are not so different. I think both can be translated as story in English, but sometimes (probably recently) they are used when people want to emphasize the coherence of the whole story. They are more about idiomatic expressions rather than nuances.
For example, typical examples may be like the following:
In these ストーリー/物語 are not interchangeable.
The former literally let the presentation have a story. The intended meaning is that the presentation is given as a single coherent story in such a way that it is understandable from the beginning to the end without (too much) diversion.
As for the latter, it is literally covid-19 as a story, and 物語として does not really mean much. The whole phrase means that the prose is composed as a single story rather than a collection of facts. It does have some connotations that the story is partly fiction, but not necessarily that the whole story is invented.
As a practical distinction, I have the impression that ストーリー is more frequently used for expressions common in business contexts.
A dictionary definition of 物語る has 'あるまとまった話をする。' . I think this まとまった話 is the closest meaning in the above usage.