One of his discussions of that issue is in Roving Commission: My Early Life (1930)
No, Sir Winston Churchill was English, of an English father and American mother.
Given that Sir Winston Churchill was born in England to a British father and an American mother, it seems a pretty safe bet to say that his first language was British English.
Churchill loved fencing (he was the school fencing champion), History and the study of the English language - he excelled at these He did not like Latin (he stubbornly studied the English language instead) and struggled with mathematics (he called them "sums")
Winston Churchill
Winston Leonard Spencer Churchill.
Winston Churchill Winston Churchill Winston Churchill
Winston Churchill
Winston Churchill.
History of the English Speaking Peoples.
Winston Churchill was a prominent English politician.
Winston Churchill was in power
No, Winston Churchill is not single.