what it can mean?

[Loiraci]

If I'd 've known = If I had have known (?) is it possible this structure? which is the verb tense?

or If I would have known (?)

I'm waiting for you. thanks.

[MrPedantic]

Hello Loiraci

"If I'd've known" ("if I had have known") is quite common in spoken English, but much less so in written English.

It is non-standard (i.e. you would not generally see it in a book or newspaper, or use it in an essay or job application, except perhaps when quoting actual speech).

It has the same meaning as "If I had known", but seems to turn up in especially emphatic contexts. You often hear it in combination with "only", e.g. "If only I'd've known!".

Other variants include: "Had he have known..." and "If I hadda known".

The grammar is very mysterious. The structure itself is old (there is an example of the structure "had he not have done X" in the works of Thomas Malory, a 15th century writer); of these uses, the OED says (from memory, so it may not be exact) that "in the 15th and 16th centuries occur many examples of redundant 'have' in the compound tenses".

_______Irresponsible Speculation________

My own theory, for what it's worth, is that such structures are the remnant of a perfect infinitive construction, from which the "to" has since been elided, e.g.

1. If I could (to) have known,...
2. If he might (to) have known,...
3. If he had (to) have known,...

But I have never seen any research to support this idea, so it's probably merely a fantasy of my own.

_______End of Irresponsible Speculation________

You do also hear "If he would have done X,...", which has the same meaning as "If he had done X" (though sometimes with more sense of "willing"). This is also non-standard, at least in BrE.

Have a good Friday,

MrP

[riverkid]

You do also hear "If he would have done X,...", which has the same meaning as "If he had done X" (though sometimes with more sense of "willing"). This is also non-standard, at least in BrE.
Have a good Friday,
MrP

Excellent analysis, Mr P.

Why do you think it is that ""If he would have ..." is called non-standard, but "If he could have ..." is perfectly acceptable?

[MrPedantic]

Well, I'm not sure I understand it either.

It's non-standard in BrE in the sense that e.g. a copy editor would probably change it, in most instances, and that "standard" speakers seem not to use it (in my limited experience).

But where the speaker wants to inject more sense of "willing" than in the usual "if he had", it seems to work, e.g.

1. Allworthy resented this reflection only with a smile; nor could he, if he would have endeavoured it, have conveyed into that smile any mixture of malice or contempt. (Fielding, Tom Jones)

2. As my heir, he would have had it all, if he would have behaved himself with common decency. (Trollope, Can you forgive her?)

The curious thing about this structure is that it manages to sound (at least, to my ears) standard but old-fashioned in a literary context, and non-standard but contemporary in a non-literary context, such as a football phone-in.

__________

I should have noted before, by the way, that "if he would have..." is standard when it follows "as", or when "if" = "whether", or where "have" is a main verb, e.g.

3. It's not as if he would have minded.
4. I doubt if he would have minded.
5. If she would only have a little more patience...

Only the usage in the protasis seems to be disputed.

MrP