I need to write a letter in an old manner. I suppose like the beginning of the 19th century.
So what was the regular phrase to get a news?
The common 19th century way to ask "what's been happening?" or "what is new?" or "what is the latest news?" is one of the following:
"What news?" (Read it again, no mistake or typo was made!) This informal idiom is often used when a person newly arrives, especially from town, a more distant place or time, or as a request for reconnaissance information. In a more formal register, this was used at the beginning of a sentence.
"What has happened | transpired | occurred..." As a query for news, this (formal) form required some qualifications to ground the question in time, an event occurring in time, or a particular subject of interest. These qualifications are often applied to formal versions of the "What news?" idiom.
Remember, the primary form of all news was when someone arrived. New information about the world was always thought of more like "important gossip": some person's information about something and relative to some time. An idealized version of this is, "What has happened since [we last met OR some-event OR some-other-mention-of-time] about [some topic]." There was little-to-no sense of "news" in the modern, abstract sense; "news" as we know it didn't even exist. And so the "What News?" idiom also worked as part of a greeting, welcoming the newly-arrived to share, which aided in the spread of important information.4
The form "pray tell" had it's heyday in the 1700's, and it was almost completely formed as "pray tell me", as the following Google Ngram indicates.
It's interesting that (as a corollary) we can conclude that the phrasing from @WhatRoughBeast's answer, "And what, pray tell, is...", is not at all representative of historical usage. Further checking shows that even simple fragments of that sentence, "pray tell is..."* and "what pray tell...", have a 0% occurrence.
The next Google Ngram suggests that plain questions were much more popular than the "pray tell" forms. For example, "tell me what..." and "tell me how...", were much more common than "pray tell me what..." and "pray tell me how...".
"Pray" does mean "wish" or "hope". But as used in a question (or command), it indicates a verbalization of such to the other person as an emphatic, urgent, polite, or excited request, like beseech, implore, command, beg, or urge. It can confer an urgency or authority to the speaker. "Pray" wouldn't usually be used to satisfy a simple curiosity of what is new or news, especially as a question to someone already known.
The following are some representative quotes from COHA (focused on 1800 to 1830). Some are from fiction, which presumably would reflect not only then-current language, but also idealized language from the past.1
Quotes: "What news?"
Quotes: "What has..."
Quotes: "What has become of..."
I pray you choose side with (and defend) historical accuracy by saying ye some words as such:
Have I not given (and in ample measure!) ammunition sufficient and necessary to defend this stance?2
But if you want to make an impression of sounding old fashioned to most people, then ironically, you're better off using an expression that "sounds" old fashioned to the modern ear, even though it's not as accurate:
And what, pray tell, is the current news?" (Credit to @WhatRoughBeast's Answer) Most people don't know that this form never existed.3
You can make it sound more old fashioned by adding verbiage and more "old fashioned stuff": And what, pray thee tell, is thine own knowledge of current news?
And what, pray thee tell, is thine own knowledge of news that is now of current significance amongst ye? This is over-the-top faux Old-Fashioned because it has more "old fashioned stuff in it" and is conflated with excess verbiage, awkward constructions, and repetitious redundancies. That's what the modern ear thinks it hears in highly stylized prose of the 18th century. Some people would hear this as just "very old fashioned speech" while others would recognize it as pretentious or comical.
To be funny, you could also say, And what, pray tell, is thine own knowledge of ye olde current news?
This answer is based on a review of COHA (Corpus of Historical American English), from approximately 1800 to 1830. Here are some of the more notable findings:
what has] was scanned for questions about news, resulting in the discovery of the "What has happened..." form (and variants like "What has occurred..."*).
The query [
what followed by
news within 8 words] clearly shows that "What news?" is an early 19th century idiom. There are no forms that containing intervening such as "What is the news?"
The phrase [
pray followed by
news within 8 words] is rare.
current news] and [
what is the news] are rare.
what is new] is only used to mean "that which is new".
1. The number of examples I give does not indicate one form is more popular than another. Also, all the examples don't show the broader context which may supply additional information such as the expected news topic to be reported. Also, I typically go to great lengths to give proper citation to references. In this case, it's not necessary. All references are from 1800 to 1840, and my links to COHA results should be sufficient.
2. I'm not really imploring you to use the historical form. I was joking a bit by assuming (my own best attempt at) an old fashioned dialect.
3. @WhatRoughBeast sounded plausible to me when I first read it. On the other hand, this answer turned out to be a pleasant, counter-intuitive lesson for myself.
4. Another way of thinking about this is that the burden of deciding "what is news" and the answer to "who, what, where, and when" is currently controlled by News Agencies, "The Media", Governments, and other special interest groups. A modern person may ask another, "what's been in the news?" and the answer is what they saw on the Internet, TV, or read in a newspaper. In the early 19th century, the burden of all these questions (what is news, who, what, where, when) was a shared (and important) part of dialogue, and so the frame (which news) and the main questions had to be made explicit (or implicitly understood).
"And what, pray tell, is the current news?"
And why, pray tell, does no answer refer to any actual content of early 19th century letters?
This might be a good place to start:
My answer will be augmented as time provides. But to be honest, I think the question is off topic.