As If vs. As Though

I think they mean the same thing. This British English page agrees (and I think most American English speakers would also agree):

http://www.learnenglish.org.uk/grammar/archive/as_if.html

I tried very hard to think of any cases in which I use the two differently, but after much wasted time I could not think of any.

thank's, that's a hell of a link you gave me here!

I have the same question for but vs. except.

For example:

"But for the names he called us, we didn't understand a tenth of what he bawled."
vs. "Except for the names he called us, we didn't understand a tenth of what he bawled."

Is there a nuance of some sort?

Very slight, and not very meaningful.

"But for" many times indicates a circumstance that prevented the happening of something else:

"But for the the extensive flooding that washed out much of the spring planting, the farm would have shown a considerable profit that year."

"Except for" most often indicates something that is literally an exception:

"Except for the farm that sustained serious flooding damage, all the farms in the area showed a considerable profit that year."

In your case, the "except for" case is marginally more acceptable to me, though there is a great deal of overlap.

Somehow, I cannot imagine the American teenage girl responding to her friend, "As though!"

"If" is more uncertain, as though you were talking about the possibility of something, rather than the actual existence of something.
"If I feel like it."
"As if!" is a shorter version of: "As if that would happen!", "As if I would ever do that!", etc.

"Though" is definitely more of a certainty, because it usually is used when referring to something as it already is.
"I was going to invite myself to dinner, though I suppose that would be quite rude."
"I never figured him for a shy person, though now that you mention it, he does keep to himself quite a bit."

'Though' is also an unfortunate bastardization of "although" that is usually much more effective and less snobbish.

"Though" is not a bastardization of "although;" this is a common misconception. Originally, the word although was actually two separate words: all though. This phrase was used much like today's phrase "even though" is used -- as an intensifier for the conjunction "though." Although many purists will argue that "though" is an unacceptable substitution for the word although, it is obvious that history does not support this claim. Feel free to use though as a conjunction, but I would be leary of using it as an adverb, as many still take issue with that as well.

Dictionary of Problem Words & Expressions (Harry Shaw) says "as if" and "as though" are pretty much interchangeable. Years ago I read in an English usage book that "as if" is preferred for this reason: "She ran out of the house as (she WOULD run) if her hair was on fire" As though doesn't make sense this way. "...though her hair was on fire"? But her hair was not REALLY on fire. Nevertheless, one is used interchangeably with the other.

I'm the same speedwell who originally answered this question, heh. I was pushed by a Singaporean colleague to sort this out, and they would not accept "forget it; they're both the same these days" as an answer. They were *interested*. So I spent some more time thinking about it, and I realised I do have an unconscious preference. (Oh, and I have code switched to British rules because I now live in Ireland.)

The difference is subtle but meaningful and has to do with *plausibility*. Imagine I were a chef in a restaurant, and I asked a server how a food critic liked the dish I cooked. They might say, with their thoughts in brackets:

- "Well, she ate it as if she liked it." (I am of the opinion that she liked it, since she ate it with enthusiasm.)
- "Well, she ate it as though she liked it." (I am of the opinion that she didn't, since it seemed like it was an effort for her to eat more than the first bite of it.)

In other words, I would lean toward "as if" if the conditional was plausible or likely, and "as though" if the conditional was implausible or unlikely or imaginary. A few more examples:

- I walked down Union Street as if Aberdeen was my new home. (I'm just a tourist, but it feels like a homecoming somehow.)
- I walked down Union Street as though Aberdeen were to be my new home. (I wanted to make myself look like a potential new resident, not just a tourist, but I'm not really going to live here.) Note the subjunctive, which, while dead as a dodo, is still used with "though" and not "if", as noted by others.

- The little Italian girl smiled as if she understood what I said. (She very well might speak a little English.)
- The little Italian girl smiled as though she understood what I said. (She didn't understand, but she was being sweet and polite.)