This question is with reference to the question I recently asked about "request you to" vs. "request that you" and I closed it that the answer found satisfiable. And also I was convinced that "request you to" might be some specific usage belongs to India/Pakistan only and native English speaker would never accept that.
However, today when I was reading the book "Oxford Guide to English Grammar", I came across a definition with an example "I request you to leave the building". Refer below image.
So which definition is correct? Why I see different definitions everywhere. The book I mentioned above must be a global reference for English grammar, right? Then why it has some example which is not even accepted by the native English speakers?
Also I need to know why should we only use "that" with "request". I need some detailed definitions with credible sources to refer.
I'm totally confused now. Please help me. Thanks in advance.
Question update 1:
This question is not just about Indian English. I believe that "request you to" is still widely used by different country peoples all over the world. I have seen numerous webpages & articles are still using that.
Also I agree that "request you to" usage is outdated in American english but I disagree that it is ungrammatical for other peoples just because they don't use it anymore.
Question update 2:
As I have got enough explanation below in the comments and discussions that the usage is no longer valid in America. Now I want to know opinions about it from other country peoples. Please comment your opinions.
Best Answer
I appreciate your raising this intriguing question that has some important implications for how or why a particular expression or construction is considered grammatical. Merriam-Webster dictionary clearly gives the example "requested her to write a paper" under the transitive verb definition of 'request' at https://www.merriam-webster.com/dictionary/request (scroll down past the extensive 'noun' definition to read) so the form 'request someone to do something' is definitely grammatical from a technical perspective.
However, it is no longer a popular usage: according to google ngrams, the popularity of both "request you to" and "request that you" peaked around the year 1830 and declined steadily thereafter. As you rightly noted yourself, "request you to" enjoyed a brief resurgence peaking around 1970 but both expressions became progressively unpopular (rarely used) in the last quarter of the 20th century, indicating that such extremely formal language has lost favor in English all aroung the world, although "request that you" is marginally ahead at the turn of the millennium:
That is not to say that such expressions are equally outdated everywhere. Based on the answers to a number of related questions on ELU and ELL, typical patterns and frequency of use seem to differ between dialects such that "request someone to do something" is more common in Indian English and "request that someone do something" is more typically used in the USA.
The extensive explanations of senior member @tchrist both in comments here and in an updated answer on ELU present a convincing argument (supported by ngrams) that the construction "request someone to do something" has become obsolete in modern American English. As regards British English,
If "grammatical" is defined as "the way native speakers are using the language now" then the extreme rarity of such usage in the case of 'request someone to do something' might well lead it to be considered ungrammatical by speakers of American English. Whereas the same form is so commonly and typically used in Indian English that as an Indian I find it extremely natural to the formal register, and unquestionably grammatical.
As a transitive verb, "request" can take an object in multiple ways.
(1) Ask for something:
Here "request" literally means "ask for" in a formal/polite sense. Whatever is being asked for is the object of "request."
(2) Ask for something from someone:
Here somebody is being asked politely for something but the object of 'request' is still "attention."
(3) Ask someone to give you something:
Here the object of 'request' is "students"; the students are being asked to give him something, and the object of 'give' is "attention." However, he is essentially asking for their attention and this is just another way of writing "He requested the students' attention."
(4) Ask someone to do something:
Here the object is 'the guests' and he is requesting them to do something. This can be rewritten in passive voice as
Whereas the alternative form "request that" sees 'request' used with the conjunction 'that' which connects it to the clause that follows:
Both these forms of 'request' are nicely described at Collins Dictionary online:
Source: https://www.collinsdictionary.com/dictionary/english/request
Note: both "may I" and "request" as used in these examples are politely formal ways of asking for something, or asking someone to do something. In this type of usage a question mark is not necessary even though the sentence begins with "may I."