I don't know how to convey the word たら in English in this context

A girl confessed her feelings to her crush, was rejected, and as a consequence
she started wondering what "好き" meant.

ずっと言えなかった言葉だ

ずっと言いたかった言葉だと思う

なのに口から出てしまっ **たら** もう正体がわからない.

So, the last sentence is something like "But after the word escaped my mouth,
I don't know its real meaning anymore". I think the sentence is a conditional,
but たら meaning "if" doesn't make sense in English. たら meaning "when" makes
more sense, but the wording is still a bit awkward "When it escaped my mouth,
I don't know its real meaning anymore"). I think it probably does mean "when"
but I don't know how to properly translate the word integrated to the whole
sentence in a way it can convey what the Japanese sentence is expressing. Or
does たら have another use here?

any reply is appreciated_!
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2018-11-02T02:31:56.850
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2018-11-02T06:51:36.227
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question
grammar meaning
use of たら in this sentence
Although たら is often taught initially as a simple conditional corresponding to
the English "if", its meaning and use is broader. Rather than a simple "if",
see V-たら as _a condition for the main clause to take place_.

That is: _as soon as V happens, something else occurs_. Which in some cases is
closer to "when", exactly as you said.

Consider this situation. I'm waiting a friend to arrive by train at some
station. I could say:

> 着{つ}いたら連絡{れんらく}してね. When you arrive, give me a call.

or, more literally, contact me. If we exclude extreme (unlikely) cases, we are
sure that this person will arrive. So, we don't really see this as "if you
arrive", which would leave the possibility that the person will not arrive
open.

Another reason to see it as "when", is that たら is the only type of conditional
where the result can be in the past. Would be weird to have an “if” when the
result has already taken place. These examples are taken from [this
link](http://www.guidetojapanese.org/learn/grammar/conditionals).

> 家に帰ったら、誰もいなかった。 When I went home, there was no one there.
>
> アメリカに行ったら、たくさん太りました。 As a result of going to America, I got really fat.

Other than the link above, I suggest you look at this [excellent
answer](https://japanese.stackexchange.com/questions/393/differences-
among-%E3%81%9F%E3%82%89-%E3%81%AA%E3%82%89-%E3%82%93%E3%81%A0%E3%81%A3%E3%81%9F%E3%82%89-%E3%81%88%E3%81%B0-etc)
regarding the different types of conditional forms.
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2018-11-02T06:51:36.227
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answer