I know that interjections え？ は？ そうか ? and 何だ？is used when we are in doubt. and
i would like to know whats the nuances between those word. here i give the
examples....

1st:

> ルフィ：おれは死んでもいいんだ！  
>  コビー： **え？**

2nd:

> ヘルメッポ：おいこのガキ投げすてろ！！  
>  海兵： **は？**

3rd:

> ゾロ：おれはおれの...やりたい事を成し遂げる！！！  
>  ルフィ：ふーん、 **そうか** 。でも おれなら一週間で餓死する自信あるけどね。

4th:

> ゾロ：仕方んねエからその辺の海賊船を狙って。生活費を稼いでた. . . それだけだ  
>  ルフィ： **なんだ** ？お前迷子か。

Can those word being substitute to one and another?
CC BY-SA 3.0
2016-12-25T04:37:50.953
41965
2017-01-03T01:20:52.403
2016-12-27T01:04:22.500
14627
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question
translation word-choice meaning nuances interjections
whats the nuances of interjections え？ は？ そうか ? and 何だ？
That's all depends.  
The following is most common usage.  
1st:  
Huh?(surprised)  
  
2nd:  
pardon?  
  
3rd:  
Hmm, is that so?  
  
4th:  
What?
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2016-12-26T02:41:03.130
41982
2016-12-26T02:41:03.130
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answer
Given they are all interjections, they all have different meaning (nuances) as
described below

1st

え？ is interjection used to show pure surprise. Translation, I can't think of
because I'm not so much fluent with English nuances.

2nd

は？ is interjection to show astonishment. It can also appeal that the speaker
has negative impression what's being said (or happened).

3rd

そうか is "I see", in English.

4th

Difficult to explain... At least, neither of above interjections can
substitute this usage of なんだ, that's for sure..
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2016-12-28T15:56:18.493
42076
2016-12-28T15:56:18.493
10859
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answer
They are kinds of injections.

え？ - It expresses surprised. Used when a speaker was surprised. Anyway, "what"
in English.

は？ - It also expresses surprised, but it expresses not agreeing a opponent's
an opinion.

そうか。 - In English, "is that so?"

なんだ？ - It's hard to explain for me, because I don't almost use the usage like
that. Its usage, "what?"
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2017-01-03T01:20:52.403
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2017-01-03T01:20:52.403
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answer