For example, you're talking to someone and he's trying to explain something to
you, and you have no idea what he's going on about. You could just say "I
don't understand", sure, but is there something more akin to the English "I'm
lost"?
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2014-05-28T06:01:54.040
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usage expressions
Is there a way to express "I'm lost" (in a metaphorical sense)
How about...

> (話が)わからなくなりました。(←わかる(解る)+ない(無い)+なる(成る)+ました)(rather than just
> わかりません。/わからないです。/I don't understand.)  
> or  
>  (話に)ついていけていません。(←つく(付く)+て+いく(行く)+て+いる(居る)+ません)(rather than just ついていけません。/I
> can't follow.)
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2014-05-28T06:22:56.753
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The expression I encounter more often among Japanese than the one by Chocolate
is

```

     訳が分からない  
     wake-ga wakar-ana-i  
    
```

The meanings of _wake_ vary. Here, we're looking at the meanings 2-4 of the
lemma 訳 (see [here](http://www.weblio.jp/content/%E3%82%8F%E3%81%91) but
scroll down a bit to find 訳), namely how something comes to be the case
(meaning 2), the meaning of what people say (meaning 3), and how stuff works
(meaning 4).  
That should cover it.
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2014-05-28T08:19:21.363
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There are several other options that grammatically I don't see anything wrong
with (though sometimes I tend to be too 教科書っぽい). Although I get the feeling
that saying any of these directly **_to_** someone would be a little off-
putting.

> **[迷]{まよ}う** ー To be lost; can be used metaphorically
>
>   * (お前の)言うことに迷っています → I'm lost on/I don't get what you're saying
>

>
>  
>  **[惑]{まど}う・[戸惑]{と・まど}う・[当惑]{とう・わく}する** ー Be puzzled; perplexed; confused
>
>   * (お前の)言うことに当惑しています → I'm confused by what you're saying
>

>
>  
>  **[掴]{つか}む・[把握]{は・あく}する** ー To grasp, hold; metaphorically as "understand"
>
>   * (お前の)言うことを掴んでいません・把握していません → I don't get what you're saying
>
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2014-05-28T18:00:10.193
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Not sure whether the expression 【[頭]{あたま}が[回]{まわ}らない】(translates roughly as "I
can't wrap my head around it", but it's an idiom so there is no perfect
translation) can be used in this way, but I am not a native speaker so I can't
tell you whether it is appropriate or whether my translation is missing
something.
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2017-05-18T02:30:51.120
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I think the most "Japanese"-like way to respond to that is to reply that you
don't understand fully. It comes up often in literature: よくわからないけど、...

...and then defer or offer support/empathy.
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