To orate is to give an important-sounding speech. If you're giving a wedding toast, feel free to orate. However, if you're giving a friend advice, it's best to avoid orating.
There are more and less appropriate situations in which to orate: a famous philosophy professor might be forgiven if she tends to orate when she's speaking about her favorite subject, Spinoza. But if you're at the dinner table, your family will probably just laugh at you if you begin a speech with Mark Antony's words from Shakespeare's Julius Caesar: "Friends, Romans, countrymen, lend me your ears!"The Latin root orare means "speak, pray, or plead."