Is it incorrect to say either of the following?
In regards to your previous email
In regards to your previous emails
I was asked this by a non-native speaker, and after thinking about it I decided that in regards to sounds more natural than in regard to. Google confirmed that I have the same intuition as most speakers by returning 73 and 110 million results for the singular and plural expressions respectively.
I came here and found the related question What alternative would you suggest to "in/with regard(s?) to"? Although my question was asked as a part of that, no one gave much of a defense of their opinion. The closest was this comment:
No, I think that's just wrong. You have to watch out, people love to make up "just so stories" about grammar. This arises in part from the very common misapprehension that all points of grammar make some kind of rational sense, when in fact a lot of the details are purely conventional. For instance, you can still say "In regard to the strawberries..." The plural there is just another (probably incoming) variant. If you don't want pedantic people to be irritated with you, then by all means don't use it. – Alan Hogue
Is this a case where the most common intuition is wrong? Can someone better explain the rationale behind the use of the plurals?
A comment mentioned Google Ngrams and I'ved posted the graphs below. In my opinion, Google search results or any other kind of Google result are only misleading if you're taking it to imply something more than what they're giving - raw data from some source.
Firstly, here are both in regard to and in regards to in the same search. The plural doesn't show up because it's so low.
Now here is just "in regards to" in its own graph so we can see it.
I suppose I should refrain from offering interpretation. I'd like for people to do that in their answers. Nonetheless, this does absolutely beg for certain conclusions to be drawn.
As a final note, Google Trends shows in regards to winning out of the two with about the same ratio as the search results.