not to speak of

not to speak of something

(slightly formal)
and possibly even more importantly It's hard to imagine a country that would use those weapons on its own people, not to speak of its neighbors.
Usage notes: used to introduce and emphasize another possibility
See also: not, of, speak
References in classic literature ?
And I couldn't bear to see our love worn away by the daily dropping of tears, not to speak of its being rent by the dynamite of daily quarrels.
But not to speak of the passage through the whole length of the Mediterranean, and another passage up the Persian Gulf and Red Sea, such a supposition would involve the complete circumnavigation of all Africa in three days, not to speak of the Tigris waters, near the site of Nineveh, being too shallow for any whale to swim in.
The robin talked this over with his mate a great deal for a few days but after that he decided not to speak of the subject because her terror was so great that he was afraid it might be injurious to the Eggs.
For a long time she did not know that she had ever had any brothers; for her father and mother took care not to speak of them before her: but one day by chance she heard the people about her speak of them.
N-nothing much, Aunt Polly; that is--I can't tell it unless I tell other things that--that I'm not to speak of.
6 million cost of supplying wind generated electricity to the island of Eigg underlines the appalling cost of this form of power, that in this case works out at about pounds 100,000 per family, not to speak of the continuing subsidies this installation will receive out of our pockets.
My question is, how come Indian and other not-so- wealthy-countries' children, whose per capita expenditure is not anywhere near the ones in the USA, not to speak of overcrowded classrooms, perform so much better?
In contrast to the space accorded the first two Gospels, Luke and John endure relatively short shrift, with the result that problems of continuity and discontinuity, not to speak of attitudes, in these last two Gospels are obscured by overly facile treatment.
and even the occult sciences (al-'ulum al-gharibah), not to speak of the supreme science or metaphysics (al-ilahiyyat) which determined the framework for his understanding of natural philosophy (al-ilahiyyat).
The gold thread signifies visual luxury without constituting it; any number of embroiderers, not to speak of Fifth Avenue maroquiniers, have produced richer cloth with less rich materials, any number of calligraphers have produced more gorgeous script, and any number of artists have undone Minimalism in more inventive and challenging ways.
But such a climate can too easily lead down a slippery slope to inefficiency and skewed incentives, not to speak of damage to America's political fiber through a weakening of the nation's democratic spirit.
Not to speak of the fact that world demand for fossil fuels will soon outpace production, fossil fuels cannot satiate our energy needs in the long term," he said.
embassies in Africa, the USS Cole and many other attacks upon America, not to speak of the World Trade Center, expresses an intense hatred of the United States.
Something of the original conception adheres in the opening chapter, a diachronic account of Visconti self-representation and appropriations of tradition, not to speak of the patronage of others.