Adverb
speaking of
(colloquial) Speaking of which; relatedly, used to introduce a related topic.
Speaking of New York as a traveller I have two faults to find with it. In the first place there is nothing to see; and in the second place there is no mode of getting about to see anything. Anthony Trollope
Speaking of Satan, I was watching Rush Limbaugh the other day. Bill Hicks
To speak today of a famous novelist is like speaking of a famous cabinetmaker or speedboat designer. Adjective is inappropriate to noun. Gore Vidal
In speaking of the work of machines and of natural forces we must, of course, in this comparison eliminate anything in which activity of intelligence comes into play. The latter is also capable of the hard and intense work of thinking, which tries a man just as muscular exertion does. Hermann von Helmholtz
Women talk about love and silent about lovers, men - on the contrary: Speaking of mistresses, but are silent about love. Marina Tsvetaeva
Speaking of the devil. English Proverb