TL;DR: According to one Australian news outlet, the change is “seen as part of a push by Ankara to rebrand the country and dissociate its name from the bird”. They quote an academic in Turkish Studies, and the country’s state broadcaster.
Nothing more official was mentioned, which is suggestive (though not proof) of there being no formal rationale given by the Turkish government. But this would certainly make sense of the push being particularly associated with the English language, even though (as other answers have shown) it’s not actually the case that the move is limited to English.
I’m in Australia, and I noticed this morning that ABC News (that’s the Australian Broadcasting Corporation, not the American broadcaster with the same acronym) was using the “Türkiye” spelling in its coverage of the recent earthquakes in Türkiye/Turkey and Syria.
The above-linked article included notes on the naming in a sidebar that I quote below in full:
Why do we call it Türkiye — not Turkey?
- The country called itself Türkiye in 1923 after its declaration of independence, but the internationally recognised name was spelled "Turkey"
- The ABC began referring to it as Türkiye after its official English name was changed in May 2022
- Türkiye is now used by the United Nations, DFAT and the US State Department, however, many media organisations are still using the anglicised spelling "Turkey"
(“DFAT” is the Australian federal government’s Department of Foreign Affairs and Trade.)
Interestingly, just an hour after I first added this answer, ABC News posted another article, titled “Confused about the Türkiye spelling with the country in the news after a deadly earthquake? You're not alone”. That article includes the following quotes from Dr Barcu Cevik-Compiegne, “a lecturer in Turkish Studies at the Australian National University”.
"[Turkish President Recep Tayyip] Erdoğan's grievance against the old name seems to be related to the humorous association of the country's name with the bird," Dr Cevik-Compiegne says. "Türkiye, it is hoped will warrant more respect for the country and give pride to its citizens."
"Since the government requested it, and some people find the bird association offensive, I think English-language media should respect that."
(Bracketed text is as in the original.)
This article also links to a news piece that completely passed me by last year, covering Ankara’s lodgement of its request with the UN: “Turkey seeks to disassociate itself from bird with Türkiye rebrand”. That article quotes TRT World, described as “Turkey's English-language state broadcaster”:
TRT World explained the decision in an article earlier this year, saying Googling "Turkey" brought up a "a muddled set of images, articles, and dictionary definitions that conflate the country with Meleagris — otherwise known as the turkey, a large bird native to North America — which is famous for being served on Christmas menus or Thanksgiving dinners".
Some other usage-related observations: As the second article linked above says, the change was not immediately effective across the ABC, let alone other media outlets. My own quick and very non-exhaustive search of ABC News articles found “Turkey” as late as June 2022 (almost four weeks after the article about the formal request to the UN), and “Türkiye” as early as November.
That’s in writing. Listening to ABC News today, I’ve heard three pronunciations: to my inexpert ear, one newsreader said /tɜkije/ (“tur-key-eh”), another said /tɜkijə/ (“tur-key-uh”), and the Istanbul correspondent said /ˈtʊəkije/ (“TOUR-key-eh”).
And lastly, the article I linked to second uses two examples of countries not pushing for their endonymous spellings to be adopted in English: Deutschland and Zhōngguó. I’m amused to note that these are two of the exact same examples used in a comment here by user Adamant (one that’s since been moved to chat). Coincidence? I wonder.
To any ABC News researchers or journos browsing this page—hi!