I know that in the following sentences "If I had known" has to be used in the place of "If I knew" to form the grammatically right sentences. What I really want be sure of is that as a native if all the 3 examples given below sound natural to you though or do you find it odd using it that way and so on? cause I've come across this to be used that way pretty often and it makes me wonder.
Please mention sequences of verb tenses in your responds too..(e.g, In the first example Subject wishes to be informed of the object's coming as s/he was on the way. looks like same time action)
If I knew you were coming, I would've arrived from work earlier
If I knew you would/were gonna come, I would've arrived from work earlier
If I knew you had come, I would've arrived from work earlier
Best Answer
OK - my background is as a native British English speaker.
1) If I knew you were coming, I would've arrived from work earlier. This is perfectly easy to understand, though as you correctly say, the grammar is not correct. "Had known" is really needed. Still, some native speakers will say this.
2) If I knew you would/were gonna come, I would've arrived from work earlier. I find use of the contraction "gonna" the worst part of this construction. I think it may be more acceptable in American English. The same comment as above applies, of course, to the verb.
3) If I knew you had come, I would've arrived from work earlier. This sounds unnatural and needs a slight pause in thought to understand. I'd suggest you avoid it.
To a British English speaker all of these constructions sound a little jarring, but in informal situations, native speakers commonly use constructions which are grammatically incorrect. There is a danger in formal situations, that a native (British) English listener will assess your level of education or ability, to be less than it really is, if you use constructions like this. That will also depend on factors like the age and background of the listener.
Incidentally, and again in British English, the contraction "I'd have" is probably more usually used, than "I would've" unless there is emphasis on the "would".