Learn English – Is “Didn’t used to have been” a valid structure

grammartenses

Are the following sentences valid:

It didn't used to happen.

It didn't used to have been there.

And if so, what tenses are they?

Best Answer

"Didn't used to ..." is a colloquialism (i.e. informal) combining "didn't" and "used to" and both are past tense, like a double negative. And like a double negative, it's not wrong, just not formal. In fact both forms are common and informal.

See http://thestar.com.my/english/story.asp?file=/2007/11/9/lifefocus/19384883&sec=lifefocus

It is used quite often by many people, including journalists:

http://www.jsonline.com/news/opinion/102182784.html

http://www.stuhenderson.com/21RACFS.pdf

By the way, although Google NGrams can be misused, I think a direct comparison here using that tool is informative here.

didn't used to vs. didn't use to

It shows that both terms are used and that "didn't used to" has gained ascendancy over the latter half of the 20th century.