のat the and of the sentence in Newbie #11.

[watermen]

Just subscribed today and really think that the lessons pdfs are wonderful. Thanks to everything in Jpod101.

Here, I have a question, in Newbie #11. The 1st sentence　いつからワシントンDCにいるの？What does the "no" means in this sentence and how to use it. Thanks a lot.

[sphere]

Other than being the possessive particle, の can have a lot of other meanings. (see sticky particle post)
In this case, I think it expresses emphasis (or "speaker's feeling" so as to say).

Written form is の
Verbal form is usually pronounced as ん

e.g.
学校へ行きます。(normal polite form)
rough english translation : "(I am) going to school."

学校へ行く. (casual form)
rough english translation : "(I am) going to school."

学校へ行くの。(emphasis on speaker's part. often found as response to question too)
(verbal: 学校へ行くん。)
rough english translation : "(I am) going to school!!!!!"

This is also often found in questions:
e.g. 学校へ行くの。 (can be statement or question if pronounced like question. hard to explain here, but when you get the hang of it, you will know when somebody meant a statement as a question or otherwise)
rough english translation : "(are you) going to school????????"

In context (imagine this made up phone conversation on a Sunday)
A: 今日は映画どう.
B: 悪い。今学校へ。
A: 日曜日なのに。学校へ行くの.
B: ええ。ちょっと用事があるの.

rough translation
A: How about movie today?
B: Sorry, I am going to school now.
A: It's a Sunday! You are going to school????
B: yup. There are some matters (to attend to).

May not be directly related, but another common use of の is as a shorthand for こと.
I am not sure whether the case I mentioned above is really a common-use case of こと, though. e.g. 学校へ行くの。 -> 学校へ行くこと.

Experts out there, please correct me if I'm wrong

[Jason]

Like sphere mentioned, the sentence ending version of の has 2 uses:

1) to add mild emphasis to a statement. It's weaker than よ.
2) a kind of informal version of か to mark a question. It's always pronounced with a rising intonation. In writing, I would put a ? after it.

Written form is の
Verbal form is usually pronounced as ん

When used as a sentence ending particle, の is never shortened to ん (except maybe in some dialects). Though it's common for other uses of の.

May not be directly related, but another common use of の is as a shorthand for こと.
I am not sure whether the case I mentioned above is really a common-use case of こと, though. e.g. 学校へ行くの。 -> 学校へ行くこと.

No, の is not shorthand for こと. You're thinking of nominalizing a verb using こと or の, and that's a completely different use of の than the sentence ending one. And in verb nomilization の and こと have slightly different nuances.

[Javizy]

It might be worth mentioning that excessive use of の in this way, especially with statements, has a distinctly feminine feel to it. The masculine version would be んだ, where the ん is a contracted form of の. This is covered in detail in the later lessons, so don't worry about it too much, just make sure you don't go around saying 今日元気のよ！and suchlike in the meantime.

[Jason]

I think the "question" sentence ending の is pretty gender neutral. It's the "emphasis" sentence ending の that has more of a feminine feel to it. And yes, no 2 ways about it, のよ* is extremely feminine. And ending a polite form sentence with の is distinctly お嬢っぽい.

*BTW, that should be 今日は元気なのよ！

[markystar]

like javizy and jason said, this is part of the のだ construction (just without the だ).

generally, you use it with questions to elicit more information about something previously assumed or understood. (i'm not sure if that's a good explanation, but... it's how i think of it):

casual:
Aさん：この肉おいしいね。
Bさん：そうだね。どこで買ったの？

formal:
Aさん：この肉おいしいですね。
Bさん：そうですね。どこで買ったんですか？

as jason said, these forms are basically gender neutral (both men and women use them).
javizy pointed out a casual masculine form:

Aさん：この肉おいしいわー。
Bさん：うん、どこで買ったんだ？

here this is pretty strong guy's style.

now compare with sentences with のだ;
if you followed standard beginner textbook japanese, i think the sentences might have been written this way:

casual:
Aさん：この肉おいしいね。
Bさん：そうだね。どこで買った？
formal:
Aさん：この肉おいしいですね。
Bさん：そうですね。どこで買いました？

these aren't grammatically wrong, but they're not natural. the のだ used in the previous examples is natural because you assume the おいしい肉 was purchased somewhere and you want to elicit that information from Aさん. it kind of conveys a sense of genuine interest in the answer.

hope this helps!

marky

[Jason]

Here's more on the explanitory の