Studies of performance reports show that working in a multilingual env

whose colleagues speak English as a second language
whose colleagues are native English speakers.

These are parallel?

Ain't as compared with incorrect usage of idiom

Dear Fame,
This is in response to your private message.

First of all, in my mind, both (D) & (E) show clear and correct parallelism, and the problem with (D) is the grave logical issue that Vercules pointed out. In my mind, Vercules has already resolved all the issues pertaining to this question, but because you asked, I will elaborate a bit.

Point #1----LOGIC always trumps GRAMMAR ---- there is no sense putting words in what would seem to be a grammatically correct order if what is said is illogical.

Point #2 --- parallelism is NOT purely mechanical --- it doesn't necessarily mean an exact plug-in verbal repeat. Parallelism operates at both the level of the word and at the level of logic. In that sense,
managers whose colleagues speak English as a second language
managers whose colleagues are native English speakers
these two, while having different wording, are precise logical parallels.

Point #3 ---- the word "NOT" can be very tricky.
In a binary category, the word "NOT" produces a precise meaning
... those who can ride a bike, compared to those who can not ....
... those who speak French, compared to those who don't ....
... those have read Moby Dick, compared to those who have not ....
For all three of those, there's a implied yes/no question that more or less exhausts the category of possibilities.

Now, by contrast ....
.... those whose favorite novel is Moby Dick, compared to ????
....those who play cello, compared to ????
Here, the nature of the comparison is a bit less clear ---- do we mean to compare all those whose favorite novel is Moby Dick with the vast majority of humanity who do not have this relationship with this one particular book? or do we mean to compare those whose favorite novel is Moby Dick with those whose favorite is some other work?
Similarly, in the second, are we really comparing all cello-players to all non-cello-players? Or are we comparing those who play the cello to those who play some other orchestral instrument?
The logic of the sentence would tell us a lot about how we had to frame the comparison, but the point is --- as soon as there are more than two possibilities, we can't just stick the word "NOT" in there and consider ourselves done.

In this question, choice (D) has .....
...has a markedly positive effect on managers whose colleagues speak English as a second language, as compared to managers whose colleagues do not.
I must say, this is a brilliantly constructed choice designed to snap all those who think about parallelism too mechanically, ignoring the underlying logic. I really like this question.
Here, category #1 = "managers whose colleagues speak English as a second language"
So the colleagues have this specific relationship with English --- they speak it as a second language.
Who would not be category #1 ----
(a) native speakers of English --- English as a "first" language
(b) folks who speak English as their third, fourth, fifth, etc. language
(c) those who do not speak a word of English
Now, logically, in the context of the sentence, do all those people have any business being lumped together? Of course not! Yes, strictly speaking, the word "NOT", indicated simply not in Category #1, would necessarily include all those people. It includes a much wider swathe of the human race than is intended by the sentence, and it's implications are utterly illogical. Once again, logic trumps grammar. This cannot be correct.

The best answer is (E) --- perfect logic, and perfect parallelism.

Does all this make sense?
Mike