Merriam-Webster Dictionary Admits `They´ As Nonbinary Singular Pronoun
(ArtsJournal Theatre)

“We will note that ‘they’ has been in consistent use as a singular pronoun since the late 1300s; that the development of singular ‘they’ mirrors the development of the singular ‘you’ from the plural ‘you`� noted M-W on its blog, “yet we don’t complain that singular ‘you’ is ungrammatical.� – The Guardian