I'm speaking of British English, not American English. I don't know where you live, but in
America, typically you do hear Spanish pronunciations.
The poem "
Don Juan" by Lord
Byron uses the pronunciation "jewin." It may be intentional mispronunciation, but it's a famous work of English poetry that uses an incorrect pronunciation.
And as for
Don Quixote --
Wikipedia sources the American Heritage Book of English Usage for the sentence: "English speakers generally attempt something close to the modern Spanish pronunciation when saying Quixote/Quijote, as [dɒŋ kiːˈhoʊteɪ], although the traditional English pronunciation /ˈkwɪksət/ or /ˈkwɪksoʊt/ is still frequently used, more in the United Kingdom than in the United States... The traditional English rendering is preserved in the pronunciation of the adjectival form quixotic, i.e., /kwɪkˈsoʊtɨk/."