EXAMPLES FROM THE WEB FOR OH
Oh, I was an Indian in my time—a reg'ler measly hop-pickin' Siwash at that.
"Oh, I see," said the younger Milbrey—his face clearing all at once.
"Oh, blessed be the sound of your voice," replied the peasant.
And oh, sir,” added Stephen, “may we crave a drop of water for our dog?
Oh, if a man only could live up to the verses he cuts out of magazines!
Oh, I see—and of course you'd like your revenge—carrying me off from him just to hurt him.
"Oh, you were mean—mean—to shame me so," and floods of tears came again.
I'd been whipped, an' starved, an' I was always prayin', 'Oh!
Oh, ma'am—you're very polite—I feel it a great compliment, I assure you.
Oh, Colonel, help me to guard against so dreadful a calamity.
1530s, interjection expressing various emotions, a common Indo-European word (e.g. Old French ô;, oh; Latin o, oh; Greek o; Old Church Slavonic and Lithuanian o; Gothic, Dutch, German o; Old Irish a; Sanskrit a), but not found in Old English, which translated Latin oh with la or eala.
Often extended for emphasis, e.g. Oh, baby, stock saying from c.1918; oh, boy (1910); oh, yeah (1924). Reduplicated form oh-oh as an expression of alarm or dismay is attested from 1944. Oh-so "so very" (often sarcastic or ironic) is from 1922. Oh yeah? "really? Is that so?" attested from 1930.