What is the meaning of ～ないでいると～


The original sentence is:

> 俺が呆れてものを言えないでいると、ハルヒはディジタルカメラを手にして、記念に写真を撮っておこうと言い出した。

I don't think the で in ～ない _で_ いると～ indicates て形 but rather I have the feeling
that ～ないでいると～ shows two situations that almost occur at the same time.

I would translate the above sentence as:

> While still in daze that I could not say/reply anything, Haruhi took a
> digital camera and said 'Let's take some photos as souvenirs'

or literally as:

> While I was in a situation where I could not express my astonishment,
> (before I could do anything), Haruhi took a digital camera and said "Let's
> tale some photos as souvenirs."




ないで is the casual version of ず(に), which is similar to the なくて form, but
instead of meaning "didn't do (verb), and...," it means "without doing (verb),
...."

> 何も言わずに走った。  
>  何も言わず、走った。  
>  何も言わないで走った。  
>  Ran without saying anything.

As opposed to:

> 何も言わなくて走った。  
>  Didn't say anything and ran.

Of course the いると part makes it more complicated to translate, as I don't
think "without" fits in naturally. I think you basically got it, but here's my
try:

> 俺が呆れてものを言えないでいると…  
>  While I was still shocked and unable to speak...

[Tae Kim's explanation of ないで and
ず(に)](http://www.guidetojapanese.org/learn/grammar/negativeverbs2)

