Pronunciation
A British documentary on the Krupp family and firm included footage of German-speakers of the 1930s who would have had speaking contact with the family, which attests the long, thus or rather than what would be the logical German spelling pronunciation, or . The documentary's narration used the English /uː/ equivalent, /ˈkruːp/. This would seem to indicate that the more prevalent pronunciations used in English, /ˈkrʊp/ or /ˈkrʌp/, are spelling pronunciations, but regardless, they are more established than /kruːp/.
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