1. While some back-formations can even become standard, Conversate is decidedly nonstandard

2. A number of back-formations are words that tend to annoy people who tend to get annoyed by words: burgle (1870) comes from burglar (1541)—and only a year before burglarize arrives on the scene in 1871; Commentate (1794—a 220-year-old upstart, that one) comes from commentator (14th century); surveil (1941) comes from surveillance (1802).