98057
Consider

> 口を開いたらつい失礼なことを **言った。**
>
> When I opened my mouth, I just **said** rude things.

Apparently this sentence is ungrammatical, since ~たら sentences in the past
tense cannot have actions performed "intentionally" by the speaker.

**Questions:**

  1. I just wanted to confirm that if we change the sentence to the present tense, it suddenly makes sense in Japanese?

> 口を開いたらつい失礼なことを **言う** 。
>
> When I open my mouth, I just **say** rude things.

Is this the case? If so, the fact that this sentence suddenly becomes
grammatical merely by changing the tense to present is quite perplexing!

  2. Is there an intuitive explanation for why intentional actions in past-tense ~たら sentences don't make sense? They seem to make good sense when translated into English (though I know English conditionals behave differently)?

* * *

**EDIT:** The source of this example sentence is [this YouTube
video](https://youtu.be/DFFGONG3kzQ?t=849) (should start at 14m09s).

> [![enter image description
> here](https://i.stack.imgur.com/CwFpo.png)](https://i.stack.imgur.com/CwFpo.png)
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2023-01-08T15:40:43.260
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2023-01-09T07:00:08.697
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question
conditionals
Why past tense ~たら conditionals can't have actions performed intentionally by the speaker?
`[V た-form]-ら` puts focus on a point on the timeline, real or hypothetical,
where some action or even has just completed. You focus this point because
something happens then.

You might perform another action.

> ご飯を食べたら出かける。

> 宝くじに当たったら家を買う。

These are examples of the second verb denoting an intentional act by the same
person as the first.

You might notice something.

> 家に帰ったら部屋の窓が開いていた。

The second verb is used in the past tense but it doesn’t denote an intentional
act. This is also true when you say 部屋の窓が開いていることに気づいた as 気づく is not something
you intentionally do.

Your action might cause another person to react in some way.

> 大声で話したら赤ちゃんが起きる。

> 大声で話したら赤ちゃんが起きた。

Your examples are both unnatural. You open your mouth to say something. You
don’t start saying something upon completion of opening of the mouth. When I
hear 口を開いたら, I would expect to hear something like this.

> 口を開いたら蝿が入ってきた。

In all these cases, たら marks some change in the course of action or event. It
works as a switch, so to speak.

Now, when you are talking about two consecutive actions actually performed in
the past by the same person, such a switch is uncalled for and たら would sound
completely out of place.

> x ご飯を食べたら出かけた。

There are other ways to connect the two actions in logically more natural
flows.

> ご飯を食べてから出かけた。

> 宝くじに当たったので家を買った。

You can still use たら if the second action is something you would or could have
done but didn’t.

> 宝くじに当たったら家を買った（のに）。

In other words, if you use an action verb in the past tense like that, it
would be interpreted as an unreal event.

Some dialects, such as Kansai-ben, use たら more liberally than the standard
variant of Japanese. As a speaker of one such dialect, I find 口を開いたら失礼なことを言う
(without つい) to be totally acceptable as a sentence about someone who
habitually says rude things, but 口を開けば would be considered more correct, at
least more formal, in standard Japanese. 口を開く is used in a figurative sense
here. たら is usually used for a concrete instance.

* * *

[Edit]

I try to answer the questions asked in the comments below, though it's hard to
answer "why".

When you say 宝くじに当たったら家を買う, you are putting yourself at the point (on a
hypothetical timeline) at which you've just won a lottery and stating what
you're going to do from that point. Hence the past tense for the first verb
and the non-past for the second.

When you talk about a sequence of actions you (or anyone else) knowingly
performed in the past from the vantage point of the present, you should have
no reason to put yourself at or particularly focus such a point in the middle.

たら is followed by a verb in the past tense when the completion of the first
action triggered some reaction or resulted in some discovery. It puts focus on
the point at which you felt the impact of such an event. A second intentional
action by the same person doesn't require or deserve such a focus.
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2023-01-11T23:29:25.713
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answer