A poster for the latest Star Wars movie:
Is that the last Jedi warrior (sg) or the last Jedi warriors (pl)? You can’t tell for sure, since the noun noun Jedi ‘Jedi warrior’ is the same in sg and pl, as in these two examples from the Wikipedia page on them:
[pl] The Jedi … are the main protagonists in the Star Wars universe.
[sg] A Jedi’s ideology and strict way of life as a worthwhile challenge to live up to is a recurring theme in the Star Wars universe.
It seems that Jedi almost always has a “zero plural” (like, say, sheep in English). In an enormous number of the world’s languages — Japanese, for example (which is relevant here) — there are no distinct morphological forms for nouns denoting an individual and those denoting a multiplicity.
(Nouns borrowed into English from such languages sometimes preserve a single form for both semantics, but sometimes accommodate to the regular sustem of English inflection: either one emoji, many emoji or one emoji, many emojis.)
Wikipedia on the source of the noun Jedi:
The word “jedi” is said to have been adapted by George Lucas from Japanese 時代劇 (jidaigeki) (meaning “period drama” motion pictures about samurai), or perhaps inspired by the words Jed (King) and Jeddak (Emperor) in the Barsoom series by Edgar Rice Burroughs, a series that Lucas considered adapting to film. The film Rogue One suggests that it relates to the planet Jedha, source of the kyber crystals used in lightsabers.
The ambigiguity in #1 was brought to my attention by Luc Vartan Baronian, who didn’t see that there was one until he encountered the movie’s title in French: Les derniers Jedi, clearly pl (vs. sg Le dernier Jedi).