I'm struggling to understand how I can change the tense of conditional
sentences.

For example, if I want to say "If I were him, I wouldn't say such things" I
presume I would say "もし私が彼だったらあんなことは言わない". But if I want to say "If I were
him, I wouldn't have said such things" should I say "もし私が彼だったらあんなことは言わなかった" ?
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2016-12-27T15:23:23.817
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2016-12-28T03:28:53.457
2016-12-27T15:48:03.967
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question
grammar conditionals
Using たら, how do I say "would have" instead of "would"
Based on my understanding (JLPT N2), your suggested sentence
"もし私が彼だったらあんなことは言わなかった" is correct.

Although in this case, I would agree with the comment on your OP above (which
seems to no longer be there, maybe it was deleted) to use なら instead, unless
there's a particular reason you want to use たら.
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2016-12-27T15:38:36.310
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2016-12-27T15:52:57.383
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answer
「あんなことは言{い}わなかった」 would be quite acceptable in non-formal speech. It would
easily be understood to mean "I would not have said ~~" by native speakers
_**if used in the right context**_.

You should, however, be at least aware that _**grammatically speaking**_ ,
「言わなかった」 is only in the simple past tense.

More formally and/or academically, you can say:

> 「言わなかった **であろう** 」 and its shorter version is:
>
> 「言わなかった **だろう** 」

It is also very natural and common to say:

> 「言わなかったと思{おも}う/思います」
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answer