The pronunciation of the titles lieutenant and colonel, given to selected army and police officers, respectively, is quite interesting.
First, the British and American pronunciations are very different in the case of lieutenant. In British English, the pronunciation is [lefˈtenənt], see and listen here, whereas in American English it is [luːˈtenənt]. Personally, I was always confused when watching English movies, because sometimes the word was pronounced [lefˈtenənt] and other times as [luːˈtenənt]. Now I understand why.
Second, the word colonel is pronounced as [ˈkɜːnl] in British English, and as [ˈkɜːrnl] in American English, see and listen here. Neither of these pronunciations is obvious from the spelling of colonel. Instead, colonel is pronounced exactly like kernel. Curiously, in French, colonel is pronounced just at it is spelled.