- Illinoisian, an inhabitant of Illinois -- is the "s" silent, as it is in Illinois?
2. "X is not a letter from home" -- from the context it seems to mean not warm and fuzzy, very unpleasant. Is that correct? Can it be said of things and people?
Sounds rather like Mao's dictum, Geming bu shi qing ke chi fan "Revolution is not an invitation to a dinner party."

Fred Neil described Karen Dalton's voice as being "like a letter from home." A nice compliment. I've never heard it used in the negative; it sounds a bit awkward. It's probably not a common enough expression to be readily understood by most people in an altered form, at least not right off the bat.
#1 is right, but to be honest you hear the term much less than you'd hear "Kansan" or "Texan" or "Virginian." Some state names lend themselves to the process better. That's why people from Indiana refer to themselves as "Hoosiers."
I believe most New Zealanders wouldn't understand you if you used the "letter from home" expression- I've never come across it before.
2. Americans (at least those I am familiar with) would probably understand "X is not a love letter" rather than "X is not a letter from home."
CK

#2 -- In the English version of the Little Red Book, the translators seem to have left out the "invitation".
“A revolution is not a dinner party, or writing an essay, or painting a picture, or doing embroidery; it cannot be so refined, so leisurely and gentle, so temperate, kind, courteous, restrained and magnanimous. A revolution is an insurrection, an act of violence by which one class overthrows another.”
I read the expression "not a letter from home" in a book written by an American author. In this context it's about a prisoner on death row who keeps assaulting his fellow prisoners and guards.
Yes, I know how the official translation reads, but given that qing ke chi fan means "invite a guest to eat" the alternative is both more accurate and euphonious (revolution/invitation).
Shilgia: I didn't recognize the "letter from home" reference, but I'm not surprised that an American was the author. There are words or expressions that are used in one area of this country and totally unknown in another. I think that television has "homogenized" our use of language to some extent, but there are still things that cause us not to understand each other.
Two examples:
When I was a child (1940s), one of my favorite items from the bakery was a bismarck (not sure of the spelling). Americans nowadays don't recognize the word unless they are of a certain age and from the Midwest; that same item is now called a jelly doughnut nationwide.
As an adult working in an office, I once said something to a coworker who responded with "Please?" I said "What?" and she repeated her question. She was from a city a few hundred miles from my own, but in that part of the country one did not ask "What?" (rather rude) or "Pardon me?" when one did not hear or did not understand what another said, but "Please?"