Sometimes, not only in English but in all languages, we want to emphasize certain situations. And then the language itself gives us devices that aren't always common, but we use them anyways, based on known and meaningful expressions.
I am very hungry
We can depict that the subject has surpassed the status of just "hungry" for they must have stayed a long time without eating. This is a known meaningful expression.
Murder is very illegal
From this, even if it doesn't make much sense in the binary nature of the word "legal", we can depict that "murder" is a crime that, morally or ethically, has surpassed the status of "illegal".
We can state that by looking at another not-so-serious crime:
Parking on the sidewalk is illegal
Yeah, we all know it is illegal and wrong. But it is a petty crime compared to murder. In some countries murder is penalized with life imprisonment, even with death penalty, while parking on the sidewalk gives you a fine and, in the worst of the cases, your car is towed.
We can still say that "Murder is illegal", of course it is, but in the sentence, the "very illegal" was made to emphasize.
When you talk about something hypothetical, you replace is/are by the subjunctive were, and for all other verbs you backshift the tense of the verb in the same way that you do for reported speech.
When you want to ask for something, you can make it more polite by talking about it as a hypothetical suggestion, rather than a simple question.
Will you mind if I say something? - simple question
Would you mind if I said something? - hypothetical suggestion
We can use the present tense say because the context makes it clear that we are talking about something that will happen in the future. See more about using present tense for future actions here.
People rarely use present tense will, but you will often hear people using present tense for the second verb- say rather than said.
In a classroom situation, you are asking the teacher for permission to speak- you can do this using
may or
can. To make a formal request, you use
may - the second meaning in the
Cambridge Dictionary:
May I say something? - simple question
Might I say something? - backshifted- hypothetical suggestion
To make an informal request, you use can - the second meaning in the Cambridge Dictionary
Can I say something? - simple question
Could I say something? - backshifted- hypothetical suggestion
You can add please to any of these options- either before or after the sentence, or before the verb.
Best Answer
The sentence "I won't be there until September" is perfectly all right. It implies that she is coming in September, but will not be there until then.
I am only familiar with "up till", not the word uptil, myself (American English). "Up till" is a shortened form of "up until", and its meaning is entirely different from "until" -- "up until", and, I assume, "uptil", is something that is currently true and will remain so until the time specified. "I will be there up until September" means almost the opposite of the first sentence, that is, she is there now and will be there until September, when she is supposedly leaving.
I guess someone could say "I won't be there up until September", meaning that the state of not being there is true now and will remain that way until then, but it is bound to confuse the listener. It's not that there's anything grammatically wrong with it, it's just that the original form is so much more common that the latter form is bound to be misunderstood.
But perhaps it is different in Indian, or British, English. Would anyone from those speaking cultures care to comment?