In a question:

```

    Tokyo e nande ikimasu ka?
    
```

how can I know what "nande" refers to, **even when I have the context** :

  * how are you going? (by bus, by car, on foot)
  * why are you going?
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2016-05-05T02:26:33.527
33944
2016-05-05T16:58:42.710
11051
question
word-choice
How do you differentiate "nande" (why) and "nande" (how, by what means)?
IMO, `何で` means `why`

```

    東京え何で行きますか
    
```

means "why do you go to Tokyo ?"

If I want to ask "how are you going ?", I would use:

```

    どうやって東京えいきますか
    
```
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2016-05-05T04:26:43.210
33947
2016-05-05T04:26:43.210
3227
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answer
I'll attempt an answer with a few observations from my rather amateurish
position:

  * The sentence is rather stilted to begin with, you probably won't hear it used in practice.
  * 何で can be pronounced both _nande_ and _nani de_.
  * Usually you'll hear people use _nande_ for "why" and _nani de_ for "with what" or "by what means".
  * Usually sentences asking "why" _start_ with the "why":

> [何で]【Nande】[東京]【Tōkyō】に【ni】[行きます]【ikimasu】か【ka】？  
>  Why are you going to Tokyo?

  * It's _possible_ to use the same word order [何]【Nani】[で]【de】[東京]【Tōkyō】に【ni】… to ask "with what", but since written as 「何で」 it is indeed ambiguous whether it's 「[なに]【nani】[で]【de】」 or 「[なんで]【nande】」, you'll either find it unambiguously written in hiragana, or with furigana, or put entirely differently:

> [東京]【Tōkyō】に【ni】[行く]【iku】[に]【ni】[は]【wa】[何]【nani】[で]【de】[行きます]【ikimasu】か【ka】？  
>  About you going to Tokyo, _how_ are you going?

While it's _still_ possible to misread that, again, most "why" questions put
the 「[何で]【nande】」 at the start of the sentence, so it would be _unusual_ to
misread this.

  * Japanese always depends a lot on context, so usually the question should be clear from the relationship between the speaker and the listener and/or the situation. In spoken language the intonation can also give the right hint, e.g. 「[なあぁんで]【Naaande】[東京]【Tōkyō】[に]【ni】[行く]【iku】[の]【no】？！」 is probably more about the "why" than the "how"...
  * There are many ways to express this differently and less ambiguous as needed, e.g.: 
    * [行く方法]【ikuhōhō】 – means/way of going
    * [行く理由]【ikuriyū】 – reason for going
    * [飛行機]【Hikōki】[や]【ya】[新幹線]【shinkansen】[で]【de】[行きます]【ikimasu】[か]【ka】？ – Are you going by plane or train?
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2016-05-05T08:56:18.087
33955
2016-05-05T09:05:46.073
2016-05-05T09:05:46.073
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answer
なんで means both "why" and "how", so なんで東京に行く? can mean both "Why do you go to
Tokyo?" and "How do you go to Tokyo?" We guess from the context which meaning
the なんで is being used for.

If you want to be clear, you can use なにで or どうやって. These words only mean
"how", so なにで or どうやって東京に行く? means only "How do you go to Tokyo?"

The reason why なんで means both "why" and "how" is that, an adverb なんで basically
means "why" and なにで means "how". However なんで is also a euphonic change of なにで,
so they are confusing.
CC BY-SA 3.0
2016-05-05T09:35:32.087
33956
2016-05-05T16:51:21.547
2016-05-05T16:51:21.547
9831
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answer
Ordinarily we use `なぜ = why` `何で = how` to distinguish. In your question case,
we can not distinguish which the sentence means.
CC BY-SA 3.0
2016-05-05T15:43:26.477
33961
2016-05-05T16:58:42.710
2016-05-05T16:58:42.710
9831
13619
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answer