What is the difference between ので and のために?

Question

When I looked up these two terms, I found the following translations:

ので: as, because (of), since, owing to, on account of, by reason of, the reason is, given that, that being the case, etc.

のために: for the sake of, in favour, for the cause of, for the purpose of, due to, because, etc.

It seems that there is overlap between the two terms. So let me try to give an example:

I was despised for speaking English.

私は英語を話すので軽蔑された。

私は英語を話すのために軽蔑された。

For this example, is there a difference between using ので and のために? If so, what is it?

Answer 1

Your second example 私は英語を話すのために軽蔑された is ungrammatical, I'm afraid. のために should follow a noun or noun form.
×「Verb+のために」 ◎「Noun+のために」◎「Verb+ために」
... So 「話すために」 would be grammatical. (You use ために after a verb or adjective.)

私は英語を話すので軽蔑された。
私は英語を話すために軽蔑された。

These sentences are correct (as far as grammar goes... I might say it as 話したために/話したので or maybe 話すという理由で depending on the context) and mean pretty much the same thing. ために sounds more literary and more formal than ので. And ために can have a nuance of "just/only because".

Another example...

彼は秘密を知ったから殺された。
彼は秘密を知ったので殺された。
彼は秘密を知ったために殺された。
彼は秘密を知ったため殺された。

All these can be translated as "because", but ために can have a nuance of "only/just because", with more emphasis on the reason than on the result. ため, ために sound more formal and more literary than ので, and から sounds more casual than ので.

Answer 2

When you use the ので pattern, it is because you are describing the reason that something has happened/is going to happen. If you can say "because", and you can flip the order of the clauses and say "so", you use ので

"I had to go home again because I forgot my book."
"I forgot my book, so I had to go home again."
本を忘れたのでまた家に帰らなくてはいけなかったんです。

Zoos are not fun, because I'm scared of animals."
"I'm scared of animals, so zoos are not fun (for me)."
動物が怖いので動物園は楽しめない。

When you use the のために pattern, it's because you want to tell the purpose of an action or thing. Basically, if you can phrase what you want to say as a "for the purpose of" or "in order to" statement, you use のために or verbために to link the two related clauses.

"I need his phone number (in order) to ask him a question."
質問をするために電話番号は必要です。

This phone is for (the purpose of) (use in) emergencies.
この電話は救急のために使う。