Religious and political divisions can split one language into two

Evidence

Perhaps we can understand what was beginning to happen if we look at the parallel cases of Urdu and Hindi. These languages arise from the same North Indian vernaculars, and they differed in the first place merely in the scripts they employed. Urdu, like aljam´ıa, is written by means of an adaptation of the Arabic script. For Hindi, the cultural and linguistic models that are admired are provided by the Hindu scriptures, and look back toward Sanskrit. For Urdu, the languages of culture are Persian, and behind that, of course, Arabic. So the source for the learned terms and cultural allusions of Hindi is Sanskrit, whereas Arabic and Persian fulfill that function for Urdu. Time, religious divisions, political history, can all tug one language apart into two. — L. P. Harvey, Muslims in Spain, 1500 to 1614, 672

Categorization

• XREF: Connects to the story of how common vernaculars diverge into separate literary languages — parallel to the Arabic/Spanish split and to Yugoslav Serbo-Croat partitioning, and to the Urdu/Hindi case she’ll encounter in discussions of South Asian diglossia. — connects to: Anti-Christian violence endangers the language-based Sinhalese unity against Tamils. — Neil DeVotta, Sinhalese Buddhist Nationalist…, 241; the MOC “The Tongue of Power: When Language Becomes the Battlefield of Empire”
• DEFINE: Aljamía defined implicitly as Spanish written in Arabic script, made parallel to Urdu’s use of Arabic script for a shared vernacular.
• corroborated: 2 independent passages support this claim — L. P. Harvey, Muslims in Spain, 1500 to 1614, 672