Consider

> コーヒー **って** 若いうち **は** あまり飲まないほうがいいんですか。
>
> Is it best to not drink a lot of coffee while you're young?

Here, is って just short for と言う, and it acting as a topic marker (は)? If so,
would the sentence change in meaning (or connotation) if って was just replaced
with an additional は (making there be two は's in the sentence)?
CC BY-SA 4.0
2023-01-02T21:27:42.337
97913
2023-01-04T03:09:23.533
51280
question
quotes topic
The role of って in 「コーヒーって若いうち**は**あまり飲まないほうがいいんですか。」
って has [various
usages](https://dictionary.goo.ne.jp/word/%E3%81%A3%E3%81%A6/#jn-147762), and
this って is short for no particular word. This one is a topic marker that is
more emphatic than は.

Generally speaking, it's okay to have more than one は in one clause when a
contrastive-wa is involved. According to [this
answer](https://japanese.stackexchange.com/a/51/5010), "There can be only one
thematic は in a sentence. If you see a second one, the second is certainly
contrastive, and the first might be".

  * 彼は背が高い。  
He is tall.

  * 彼は背 **は** 高い。  
He is tall _(at least, although he lacks something)_.

However, your sentence does not have two は strictly, and the following
sentences sound almost the same to me.

  * 彼女って両親 **が** 政治家なんだよ。  
彼女って両親 **は** 政治家なんだよ。  
As for her, her parents are politicians.  
(No contrastive-wa is involved)

So grammatically speaking, I think って is not necessarily a precise replacement
of は. Sometimes って is just an expression to give a broader topic, and it
doesn't necessarily stop the existence of a proper thematic は.
CC BY-SA 4.0
2023-01-03T03:42:28.070
97919
2023-01-03T06:27:15.383
2023-01-03T06:27:15.383
5010
5010
97913
answer
The って is a topic marker, but not a replacement for は. It is rather a choice
between は and って, the latter of which is better due to the lack of repetition
**when it is possible to use って** at all.

  1. コーヒーって若いうちはあまり飲まないほうがいいんですか。
  2. コーヒーは若いうちはあまり飲まないほうがいいんですか。

are both ok, but 1 is more commonly used. Double は is possible, but my
impression is that it tends to be avoided if possible.

On the other hand

  3. コーヒーって若いうちはあまり飲まないほうがいい

is odd if not completely unacceptable. In this case, コーヒーは若いうちは... is
definitely better. Some sort of ending would be required to make it natural.

  4. コーヒーって若いうちはあまり飲まないほうがいい{らしいよ, ですよね}

Both versions of 4 would be better to me than コーヒー **は** -equivalent.
CC BY-SA 4.0
2023-01-04T03:09:23.533
97945
2023-01-04T03:09:23.533
45489
97913
answer