"can I" and "may I"

<In such circumstances, to use "can" for requests would somewhat rude here, and to use the imperative for requests would very rude.>

Even if speaking to a close friend or family member?

<Is that true that "may" is more used by the British than by the Americans?
And is that true that a British person would use "may" where an American would use "can"?

Thank you <

No and no.

>>Even if speaking to a close friend or family member?<<

I was specifically *not* speaking of such cases, but rather various contexts with strangers such (in particular) sales transactions, which tend to be specifically *far* more polite (and thus formal) than speaking to close friends or family.

I see you also use "thus". Is that regional?

"Thus" is not regional. It is formal, though.

<"Thus" is not regional. It is formal, though.>

Sounds biblical to me.

0 ;-)

Don't say may unless you are in the company of the queen. If you say it in Australia we will think you are up yourself..
I never hear it used here.
I say "Can i please go to the library?" and my mum is way strict about being polite.

say may I if u dont know someone at a bus stop,

I've never heard the "mayn't" form here in the UK....it certainly isn't an everyday expression and that's for sure. It sounds archaic but neither have I consciously come across it in the classical literature of the English Language but perhaps it's lurking there somewhere in the dusty tomes.

"Can I" versus "May I". Strictly speaking the latter is the correct form but the former is the one which most people use in everyday speech, but when you think of it "can I" really asks whether I have the ability to perform an action. "May I" seeks permission to perform this action, as has been said in this this thread, but you'd be hard pressed to hear anyone use it in "normal" conversation. As usual, I speak from a British angle.....maybe it's different beyond the bounds of this Sceptered Isle.

I disagree. "Can I" is synonymous with "may I" in the sense of seeking permission but might be considered informal by some.

<"Can I" versus "May I". Strictly speaking the latter is the correct form but the former is the one which most people use in everyday speech, but when you think of it "can I" really asks whether I have the ability to perform an action. >

That is not strictly true. "Can I" as an alternative to "may I" has been used to request permission for centuries. Each modal verb has more that one use, you know?

"May I smoke in here?" = do you permit me.

"Can I smoke in here?" = is it allowed.

That's the official line we've used since the year dot of modals. That more people choose the latter over the former in contemporary use in most situations, may have something to do with how we now see authority.

One thing I find interesting is that most of this discussion is being framed purely in terms of only "can I" and "may I", and ignores similar usages that correspond to (at least historically) subjunctive forms, such as "could I", "should I", and "might I" (corresponding to the modern German subjunctive forms "könnte ich", "sollte ich", and "möchte ich"). While "could I" is effectively equivalent to "may I", it seems to have slightly different connotations. "Should I" seems somewhat different from "can I", "may I", or "could I" in that it is primarily used for requests which one thinks that the requestee may want fulfilled.

On another note, "might I" seems close meaning-wise to "may I" and "could I" (it is directly related morphologically to "may I"), and is potentially even more formal than "may I", but seems to have somewhat different connotations from both; in particular, it seems to imply that the request in question is not one that must necessarily be fulfilled, but rather than one is only asking if one could potentially do that which is being requested. Note that it seems to often be used in a fashion similar to German "möchte ich", even though normally English "might" and German "möchte" differ quite significantly in their actual meanings and usage.

May not I? What the fu...

I would say that it depends on whether you use the words in written or spoken form. In written form, I would use the latter one in order to be as clear as possible. A good example was included in M56s post, involving smoking which by the way is a bad thing. ;) In addition, as Candy pointed out. The use of “May I” when used in spoken form is done to emphasise that you are being polite. (otherwise, for a more formal use, given a specific situation).