Use of ら conditional form plus なら


I need some help with the grammar in this sentence:

> ボストンに居たらなら、何で会いに来なかったんだい。

I understand the conditional -たら form and the なら conditional alone. But I have
not seen the two together.

Does the sentence simply mean If you were in Boston why didn't you come to see
me? If so, why are both conditionals used? Is this for emphasis?




> 「ボストンに **居{い}たらなら** 、何で会いに来なかったんだい。」

「居た **ら** なら」 is incorrect. At least, it is highly substandard because there
is no point in using both 「たら」 and 「なら」.

The correct and standard forms would be:

  * 「居た **の** なら」

  * 「居た **ん** なら」 (informal form of above)

  * 「居たなら」

While it is true that a very small group of native speakers use 「たらなら」
occasionally, I would personally never recommend that Japanese-learners use
it. If one did, people would notice it.

The sentence means exactly what you stated.

> If so, why are both conditionals used? Is this for emphasis?

It is only a misuse; It is not for emphasis. Then again, people who use that
"double-if" may actually be aiming for emphasis. It beats me.

