だ

[Ertai87]

So I've been wondering about this, and maybe someone can answer. I learned in Japanese class that when talking in plain style, you replace です with だ. However, this sounds really weird to me somehow, and it makes more sense to sound weird and just use the standard です than use だ. So when exactly is だ used in common Japanese speech (i.e. I don't care about "proper grammar" or the like)?

[Nytyngayl]

I'm sorry to have to tell you, but だ is basically the default casual-speech sentence ender. Depending on various speech patterns (men vs women, northern dialects vs souther dialects,　etc.) it may or may not be actually present.

For example, the sentence 日本語が好きです　could become 日本語がすきだ　although more common would be 日本語好き.

As another example, 大好きです would become 大好きだ。

Casual speech patterns tend to disregard "proper grammar" in any case, as most particles can be removed if it is obvious what is being spoken of in the sentence. Women might end a sentence with わ etc. etc. It all really depends on the dialect you're learning.

[tetekmakhang]

well you'll have to get used to using だ. it's really weird to be speaking to your friends and use です. it's like there's a wall separating the both of you from getting close. for example would you ever say to your mother "pardon me mother, but i'd like to excuse myself to the powder room"?
hell no! you just say "mum, i'm going to the toilet". get me?

so on to your question, when and more importantly, how do we use だ naturally?

you've learnt in class, all you have to do is substitute です with 　だ.
THIS IS ONLY A HALF-TRUTH.　while it's true for most sentences, it doesn't really apply for sentences that end with a です. for those sentences you just dont use anything.

a good example has already been given by Nytyngayl (btw are you vietnamese? i have some good vietnamese friends and your nickname looks very veitnamese-ey to me):

日本語が好きです is usually just said as 日本語が好き
im not a native japanese speaker so i'm not 100% sure why, but i have never heard anyone say 日本語が好きだ. maybe coz if u say it that way, it sounds very abrupt and very forceful. my reason for thinking so, is that whilst i've never heard anyone end their sentences with だ in normal daily conversation, in animes or dramas, there are those scenes where the guy screams out that he loves the girl (好きだ～！！）　on some mountain in the middle of nowhere. so maybe in circumstances where u wanna be forceful, i guess u could end with だ, but usually it's just nothing.

other examples:
1. 私は太郎でこちらは次郎です。　---> 俺太郎、こいつ次郎
i am Tarou, and this is Jirou

2. パソコンがほしいです。 ---> パソコンがほしい
i want a pc.

3. キュウリがきらいです。　---> キュウリきらい
i hate cucumbers

however there is an exception to this. if the thing preceding the だ is ん　or なん then it's ok to end with だ.

eg:
1. 実はあの人は女なんだ
actually that person is a woman

2. あいつバカなんだ
s/he's an idiot

3. 俺金ないんだ
i aint got no money


but apart from that　(sentences NOT ending with です）, yeah u can just substitute です with だ:

1. 今日きれいですね　---> 今日 きれいだね
well you're looking pretty today aren't you

2. 好きですよ　---> 好きだよ
i love you

3. ちょっと手伝ってほしいことがあるんですけど　---> ちょっと手伝ってほしいことがあるんだけど
there's something i'd like you to help me with for a little bit...


what i've taught you is how males speak in and around the tokyo area since i'm a guy and im living in tokyo.

this だ thing differs with places as nytyngayl has already pointed out for us. peopl in osaka use や instead of だ, and で　instead of よ

eg: 　これ最高だよ！　---> これ最高やで！
this is awesome!

also, feminine speech in tokyo is also slightly different. in the sentence ～なんです some girls cut off the です after the なん, and change the　ん　to　の

eg: あなたが好きなんです ---> あなたが好きなの
i really love you
(btw if you're a guy and you dont wanna sound like a pussy then i recommend NOT ending your sentence with なの ;-p


lastly, nytyngayl has brought up an interesting thing about women using the feminine particle わ.
eg: そんなことないわよ！
that's not true! / there's no such thing as that!
you see a lot of that in mangas and dramas, but the weird thing is nobody actually uses it. i was really surprised when i first came to tokyo....until i realised that this was coz the girls that i knew were all in their late teens or early 20's. apparently japanese like any other language changes with time, and girls nowadays don't use わ in that sort of feminine　speech way
so to confirm my theory, i started talking to the nice lunch ladies (already in their 40's/50's i think) in the cafeteria at my university and guess what, some of them use it.


well, this has been a very long post, if theres something u dont get, feel free to ask

[Ertai87]

So basically it's like I thought...です is only replaced with だ if something comes after it in the sentence. It just sounds really weird to me ending a sentence with だ.

[tetekmakhang]

lol....ouch. it sucks when someone summarizes what you just said in 2 lines. but yeah, you're correct. but don't forget the exception that i said :-)

[Ertai87]

I'm a guy irl, so I don't think I'll be using わ very often XD

We did learn about all that stuff in class (よ, ね, わ, の, although for some reason we didn't learn about な even though it seems very useful in male speech)

[Nytyngayl]

No, I'm actually American, but I was bored with the regular spelling of "Nightengale" so I livened it up a little.

Yeah, see my Japanese teacher at University had us using this really old book last year (and she herself is around her 40s or 50s) so we were taught わ　わよ　だわ etc.

I never actually used it, but that's what we were taught and it got me the points on the test.

And again, it also depends on the regional dialects.

Oh and I admit that I did forget about abruptness. The thing with most Japanese that I've noticed, have been told by my teachers, and the various exchange students that I've known is that Japanese are very hesitant to force their opinions on someone else, or to speak abruptly and matter-of-factly about what they think.

あの、　これはいいと思うんだけど。。。 for example, "Um, I think this is probably good" or something close to it.

だけど　and ですけど for different levels of politeness, as well, だけど being less formal.