Hi,
Which is correct?
Jay would have done better at the contest had he able to speak English.
Jay would have done better at the contest had he been able to speak English.
Jay would have done better at the contest if he were able to speak English.
Jay would have done better at the contest if he had been able to speak English.
Numbers two and four work well.
Number one is ungrammatical (incorrect without the "been")
Number three is used, since his deficience no doubt continues, but 2 & 4 are better, because they emphasize his condition at the time.