The meaning of kindly is hopefully clear: "kindly help me" means "please be kind and help me" (or "please help me out of kindness"), etc. It's a word used for polite requests; a bare "help me" is impolite relative to "kindly help me".
If you're asking why kindly is more common in Indian English than elsewhere, it's just one of the hundreds of things that have remained in Indian English long after they have gone out of fashion elsewhere.
Searching Google Books for "kindly do this" and looking through the first ten pages, most results, besides a few from India, seem to be from British and some American books, pre-1920. Examples:
"If our friends will kindly do this for us, we shall feel indebted to them." [The Penny Protestant operative, 1842]
"Would you kindly do this?" [Letter from Florence Nightingale, ≈1886]
"If you will kindly do this, I will be very thankful" [Southern and Southwestern Railway Club, Atlanta, 1914]
"If you will kindly do this I will pay you for the two together" [Anthony Trollope, 1864]
"Would you kindly do this library another favor and again place it under obligation?" [Washington State Traveling Library, 1913]
and so on and on (there are hundreds of results), and most interestingly, one 1886 book showing it must have been standard in England:
The first thing that strikes you on landing in America is the want of deference and courtesy among all classes. Not only from the inferior to the superior, but vice versa also. The maxim noblesse oblige has no sway there. In England, speaking to an equal or a social inferior, "Kindly do this," or "Please give me that," is general. In America the "kindly" and "please" are carefully omitted…
[From context, he doesn't mean it's used only with inferiors, but even with inferiors.]
Anyway, given that kindly was standard, this word for politeness entered India when English did—during colonial rule—and it has stayed on. Why something has continued to exist is not a question that can be answered (inertia?); perhaps the right question is why it went out fashion in the UK and US. (And I'd be interested to learn.) My guess is that either the phrase became clichéd, or such politeness came to be deemed excessive. In the US it seems to have taken on a slightly sarcastic meaning: Wiktionary says
kindly
2. (US) Please; used to make a polite request.
Kindly refrain from walking on the grass.
Kindly move your car out of the front yard.
Usage notes
(please): Kindly is used in a slightly more peremptory way than please. It is generally used to introduce a request with which the person addressed is expected to comply, and takes the edge off what would otherwise be a command.
Well, in Indian English it happens to have retained its original meaning, is not peremptory, and is a request rather than an expectation. (And in general it seems safe to assume that Indian English expressions are not sarcastic, and to take them at face value.)
There are only two kinds of documents in current usage that spell out the year -- legal documents, and wedding invitations.
Legal documents normally spell the year in lowercase, such as in this numbing bit of prose from West Virginia:
For any tax imposed under the provisions of this article with respect
to any taxable year prior to the first day of January, one thousand
nine hundred eighty-three, a resident individual shall be allowed a
West Virginia exemption of six hundred dollars for each exemption for
which he is entitled to a deduction for the taxable year for federal
income tax purposes.
Some legal documents capitalize everything for extra pomp, but it's uncommon:
In testimony whereof, I hereunto subscribe my hand and affix the seal
of said Court, at Office, in Nashville, the 6th day of December in the
Year One Thousand Nine Hundred Eighty-Four and in the 209th Year of
American Independence.
Wedding invitations, as noted, tend to capitalize the first letter only; however, this seems to be the only justification I can find:
The “T” in Two thousand doesn’t have to be capitalized but everyone
does it so it would probably look incorrect if it wasn’t and it will
look more polished if it is capitalized.
So, in modern usage, it appears that the rules for capitalization are:
- Spell the year out in lowercase.
- Except in wedding invitations, where the first letter is capitalized because everyone does it.
Best Answer
TL;DR:
I'd hate for anyone to walk away with the idea that Indians think 'i' is acceptable. You won't find it in any respected Indian publication. You won't find the average Indian writing it down on paper. It's just textspeak and that's why it's common in text and tweets and comments online.
Detailed answer:
I’m from India. I assure you there’s no such thing as the lowercase 'i'. No grammar teacher of mine — and I've had quite a few good ones — ever so much as mentioned it. In fact, this is the first I'm hearing of it.
The tendency of Indians to write in textspeak is unfortunate, but 'i' is as erroneous as 'u'.
I'd like to point out that almost all of these violations occur in the electronic medium. Nobody writes 'i' on paper. They type it. And if there's no autocorrect, most of them can't be bothered to rectify it themselves.
Based on my experience, this is pretty established, but not so much among Indian English speakers as among Indian netizens.
If you mean the limitations regarding the tiered system of politeness, then no. The tiered system affects more pronouns than 'I', and affects verbs and modifiers as well.
I might as well mention that Hindi's script Devanagari (or any other Indian script I'm familiar with) does not have the concept of capital and small letters. So, the question of whether this practice is a carry-over is moot in this case (unlike that of some European languages).
Don't know about the link, but I can confirm that what you have there is a practice evolved solely for digital media. Admittedly Indians use it a bit more, but it's not exclusive to Indian English and shouldn't be considered a part of it.
I don't know what article Jeega was referring to, but that was just an opinion piece, an opinion he seemed to agree with. But it's definitely NOT a feature of Indian English. I'll eat my words if anyone can provide a shred of evidence to the contrary.
EDIT: Sumelic seems to have unearthed the article link in his answer below.