Can someone explain to me the use of the vocabulary word 止まる in the context sentence below?
心ぞうが止まるかとおもった。
I was so surprised I thought my heart leapt into my mouth.
Since 止まる is listed as “to stop” I am having a hard time understanding the nuance of using this particular word in this sentence.
Thank you.
Cindy
I assume that it’s a turn of phrase, since the literal translation of that phrase appears to be:
I thought my heart would stop
That seems so clear now. I have been taking the english sentences and picking out the words that would be placed into the Japanese sentence.
Apparently I should be going the other way. The english sentence seems to be very different in sentiment from the Japanese; at least it seems to me.
Thank you for the help!
No, it’s just that the English sentences tend to be very loosely and liberally translated. The English translation should be used to get more a rough feel for usage, not as a 1:1 map to the Japanese grammar and word usage. Definitely don’t try to reverse engineer the Japanese from the English version. You will often get confused.
I personally don’t feel like it is loosely translated. It’s translated and localised. They employ English turns of phrase that capture (to their mind, everything is debatable) the same spirit as the Japanese version, to most clearly convey the ways that the Japanese version is used.
Honestly think I understand “I thought my heart would stop” much more than “I thought my heart leapt into my mouth”, though.
Yeah, I don’t necessarily disagree. Maybe they were trying to underscore how it also has metaphorical usage by using an evident metaphor in the translation.
So, how common is the phrase “I thought my heart leapt into my mouth”. English is only my second language, but that saying sounds awkward to me in English. Is it old? Not very common? Specific to a certain region (like Canadian English, Australian, etc.)? Just curious since I’m fairly good at idoms and such despite English being my second language.
Or is it just a metaphor as @Omun said? In which case, that metaphor is awkwardly phrased in my opinion. (Changing “mouth” to “throat” would make it less awkward and more a common phrase/idiom and still be different if that was what they were shooting for.)
It feels old-fashioned to me. I’d certainly never use it in conversation, and I don’t think I’ve ever heard it spoken aloud either.
… And sticking that precise phrasing into Google gets me precisely two results: this thread, and a Quizlet page using WaniKani example sentences as flashcards.
Aye, that at least gets 47,000 Google results. Still not an exceedingly common phrase. Meanwhile, “my heart stopped” gets just over a million, though admittedly more than a few of those would probably be literal.
Yes, to my ear that sounds like something out of a 70s drama.
Sounded to me like something I would’ve heard on some drama in the late 70s.
As a native english speaker, I have never heard the phrase “my heart leapt into my mouth.”
I have however said often, “OMG, I was so surprised I thought my heart would stop.” Yeah, that I have said a lot.
I’m a 47-year-old native English speaker. I’ve never heard of it and never said it. So I don’t think it is common.
I don’t disagree - and I’m not even a native English speaker, so I have less experience on the commonality.^^ It’s why I mentioned it’s localised to the discretion of the translator. It didn’t mean to say they made the best choices at all times, but I think the overall point stands about capturing the spirit of the turn of phrase.
Maybe it’s localised to Portland. 
I get what you are saying.
It just seems odd to me that they complicated that particular translation with a phrase I’ve never heard of and doesn’t use the vocabulary word highlighted at all, when they could have done a more direct translation that would have used the vocabulary word and would have been more common in usage.
I could see it being used in the Pacific Northwest.
Glad to know my sense of the commonality of the phrase was right. Thanks everyone! I have read books almost exclusively in English since my mid-teens And I am a bookworm, so not recognizing the phrase at all mayde me wonder/curious. 
I’ve seen it, mostly in writing, I think, and most of what I read is British English. I’m not native, but this phrase doesn’t strike me as odd.
One of the easiest mistakes to make in a new language, is directly translating what you think is a straightforward phrase, while not realizing how weird and unintelligible it might sound in the target language. I think this pairing of translations illustrates that pretty well, and this discussion helps make us extra aware of such pitfalls. I know I have made these kinds of mistakes, either knowingly, when I just couldn’t think of a right way to express my thoughts, with the idea of then discussing it, teaching eachother a bit more about eachother’s language in the process, or unaware I was saying something weird.
Thanks for the reminder, I should have said a native American English speaker since the two are quite different in certain respects. 