<p>Well, I must say the answer provided by user12473 is not "colloquial".</p>

<p>For asking the birthday, you can say 你什么时候生日, 你生日什么时候, 你什么时候过生日, 你生日在什么时候. Note that there's no use of 的 in colloquial language.</p>

CC BY-SA 3.0
2016-02-15T04:44:57.997Z
I disagree with your last sentence - who says you can't use 的 colloquially?!? Use it as much as you like! That's why it's colloquial - but otherwise this is right.
congusbongus
CC BY-SA 3.0
2016-02-16T07:14:35.397Z
If you can read simplified Chinese I recommend this [article](http://www.yangzhiping.com/psy/wenxin02.html) to you, it introduces why we should avoid using too much "的".
Lucius Hu
CC BY-SA 3.0
2016-02-17T07:49:03.697Z
I think this is about what people actually say, not what someone somewhere thinks we ought to say.
Olle Linge
CC BY-SA 3.0
2016-01-18T06:14:53.537Z
2016-01-18T06:14:53.537Z
Lucius Hu
<p>'你的生日是什么时候？’seems more natural than '你的生日什么时候？' But it does not mean that '你的生日什么时候’cannot be used in certain situations. Otherwise, it seems to me that '你生日什么时候？' sounds more natural than '你的生日什么时候？’. I do not know exactly the reason for this. It is possible that this relate to the number of characters in one utterance. </p>

CC BY-SA 3.0
2016-02-17T14:45:40.640Z
2016-02-17T14:45:40.640Z
Shudong
<p>In my ears, 你的生日什麼時候？ sounds more authentic than 你的生日是什麼時候？  Which of the phrasing is more common might depend on location though.  As a non-native speaker, one should remember that nouns or pronouns can be predicates in Chinese.  Sometimes non-native speakers are influenced by their native language and add 是 as copula, even though it is not necessary.  Other examples of sentences, where nouns or pronouns are predicates:</p>

<p>一瓶水多少錢？</p>

<p>外面二十度。</p>

<p>他們中國人嗎？　(In this sentence 他們是中國人嗎？ would put emphasis on 'being Chinese' and increase the tone of doubt.)</p>

CC BY-SA 3.0
2016-02-17T05:15:00.590Z
2016-02-17T05:15:00.590Z
MunHo
<p><em>你的生日是什麼時候?</em>
(When is your birthday?) is the proper way to propose a question.
<em>你(的)生日什麼時候?</em> is gramatically incorrect but seldom heard when speaking for shortness</p>

<p>Also, 
<em>你(的)生日是哪一天?</em>
(What day is your birthday?)
and, <em>你什麼時候生日?</em>
are frequently used for asking about birthdays.</p>

<p>These can also be used in many other occations. For example:</p>

<ul>
<li><em>你什麼時候出去的?</em> (When did you get out?)</li>
<li><em>你們什麼時候要走(=離開,出發)?</em> (When are you guys going to leave?)</li>
</ul>

<p>These are really colloquial way to speak</p>

<p>I'll take the last one when speaking :-)</p>

CC BY-SA 3.0
2016-02-15T01:46:18.020Z
“你生日什麼時候？” totally makes sense for me.
Ziyuan
CC BY-SA 3.0
2016-01-12T05:07:15.317Z
2016-02-14T20:51:05.053Z
2016-02-14T20:51:05.053Z
CieloAzul
<p>I would like to know if the verb 是 (shi) is optional?</p>

<ul>
<li><p>你的生日是什么时候？ (Ni de shengri shi shen me shi hou?)</p></li>
<li><p>你的生日什么时候？ (Ni de shengri shen me shi hou?)</p></li>
</ul>

<p>Which of those two sentence used more?</p>

CC BY-SA 3.0
2016-01-11T14:29:59.500Z
jukuu's 1st 10 examples for "when is your birthday" all have ＂是＂，also note:你的生日是哪一天?
user6065
CC BY-SA 3.0
2016-01-11T14:37:05.087Z
你的生日是什么时候 is a little more formal. 你的生日什么时候 is acceptable in casual conversations.
Stan
CC BY-SA 3.0
2016-01-11T15:01:07.537Z
according to e.g. "外国人实用现代汉语语法＂there are the following types of simple sentences, (1)subject-predicate 主谓句,(2)Non-S-P 非主谓句 (a)subjectless 无主句 (b)one-word 独语句 (c)elliptical 简略句。If verb ＂是＂is omitted it becomes an elliptical sentence,简略句都不能离开上下文，对话时常用简略句，简略句只能在一定的语言环境中使用，也就是说不能脱离当时环境和上下文。
user6065
CC BY-SA 3.0
2016-01-12T05:54:49.183Z
I would never say `你的生日什么时候`. It's quite weird. If you really prefer this, I suggest say `你的生日什么时候啊`
AGamePlayer
<grammar><usage><verbs>
Do I have to include 是 in 你的生日(是)什么时候？
# Do I have to include 是 in 你的生日(是)什么时候？

(Asked by: username_0 on 2016-01-11)

I would like to know if the verb 是 (shi) is optional?

* 你的生日是什么时候？ (Ni de shengri shi shen me shi hou?)
* 你的生日什么时候？ (Ni de shengri shen me shi hou?)

Which of those two sentence used more?

**Tags:** grammar, usage, verbs
> **Comments:**
> **username_1**: jukuu's 1st 10 examples for "when is your birthday" all have ＂是＂，also note:你的生日是哪一天?  
> **username_2**: 你的生日是什么时候 is a little more formal. 你的生日什么时候 is acceptable in casual conversations.  
> **username_1**: according to e.g. "外国人实用现代汉语语法＂there are the following types of simple sentences, (1)subject-predicate 主谓句,(2)Non-S-P 非主谓句 (a)subjectless 无主句 (b)one-word 独语句 (c)elliptical 简略句。If verb ＂是＂is omitted it becomes an elliptical sentence,简略句都不能离开上下文，对话时常用简略句，简略句只能在一定的语言环境中使用，也就是说不能脱离当时环境和上下文。  
> **username_3**: I would never say `你的生日什么时候`. It's quite weird. If you really prefer this, I suggest say `你的生日什么时候啊`  

---

## 4 answers

### Answer by username_9 on 2016-01-12. Score: 5 | Accepted answer

*你的生日是什麼時候?*
(When is your birthday?) is the proper way to propose a question.
*你(的)生日什麼時候?* is gramatically incorrect but seldom heard when speaking for shortness

Also,
*你(的)生日是哪一天?*
(What day is your birthday?)
and, *你什麼時候生日?*
are frequently used for asking about birthdays.

These can also be used in many other occations. For example:

* *你什麼時候出去的?* (When did you get out?)
* *你們什麼時候要走(=離開,出發)?* (When are you guys going to leave?)

These are really colloquial way to speak

I'll take the last one when speaking :-)

> **Comments:**
> **username_10**: “你生日什麼時候？” totally makes sense for me.  

---

### Answer by username_4 on 2016-01-18. Score: 3

Well, I must say the answer provided by user12473 is not "colloquial".

For asking the birthday, you can say 你什么时候生日, 你生日什么时候, 你什么时候过生日, 你生日在什么时候. Note that there's no use of 的 in colloquial language.

> **Comments:**
> **username_5**: I disagree with your last sentence - who says you can't use 的 colloquially?!? Use it as much as you like! That's why it's colloquial - but otherwise this is right.  
> **username_4**: If you can read simplified Chinese I recommend this [article](http://www.yangzhiping.com/psy/wenxin02.html) to you, it introduces why we should avoid using too much "的".  
> **username_6**: I think this is about what people actually say, not what someone somewhere thinks we ought to say.  

---

### Answer by username_7 on 2016-02-17. Score: 0

'你的生日是什么时候？’seems more natural than '你的生日什么时候？' But it does not mean that '你的生日什么时候’cannot be used in certain situations. Otherwise, it seems to me that '你生日什么时候？' sounds more natural than '你的生日什么时候？’. I do not know exactly the reason for this. It is possible that this relate to the number of characters in one utterance.


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### Answer by username_8 on 2016-02-17. Score: 0

In my ears, 你的生日什麼時候？ sounds more authentic than 你的生日是什麼時候？ Which of the phrasing is more common might depend on location though. As a non-native speaker, one should remember that nouns or pronouns can be predicates in Chinese. Sometimes non-native speakers are influenced by their native language and add 是 as copula, even though it is not necessary. Other examples of sentences, where nouns or pronouns are predicates:

一瓶水多少錢？

外面二十度。

他們中國人嗎？　(In this sentence 他們是中國人嗎？ would put emphasis on 'being Chinese' and increase the tone of doubt.)


---

