How to say

[mahesh.bhalerao]

I wanted to know , when i am driving a vehicle and somebody called me on my cell.

which is the most sophasticated way to tell him/her that i am driving.

Is is ok to say "I am on the drive please call me after some time" ?

Please oblige me with your knowledge.

Thanks in advance,
Mahesh

[colloquium]

I'm driving at the moment; can you call me back later.

I'm not a teacher.

[David L.]

I am not aristocratic, nor hob nob with such a coterie, to provide you with 'the most sophisticated' response; but here goes:

"Oh, hello, matey. Bad timing, I fear. Unlike good red wines, I do 'travel' - like, right now. So, dear boy, can't parlez vous at the moment. Can we catch up later at HRH's over cocktails? Hate to be a drag but the gendarmerie, you know."

However, fortunately for me, I think you mean 'the most colloquial yet 'proper'' response.

If the person is a native speaker and a friend:
"Oh, hello Paul. Look - I'm on the road at the moment. Can you call me back in, say, half an hour?"
or
Oh, hello Paul. Look - I'm in the car at the moment. Can you call me back in, say, half an hour?"

If business:
"Oh, hello Mr. Smith. I'm sorry, but I'm in the car at the moment. Are you able to call back in, say, half an hour?"
Neither mention 'driving', but the native speaker understands that this is implied.

If the person phoning you is not a native speaker, and not really fluent, then:

Oh, hello Paul. Look - I'm driving at the moment. Can you call me back in, say, half an hour?"

Other posters will give you a few more choices.

Note: I am making a polite request...so why don't I use 'could'?
This isn't just a polite request - for the caller's part, he might have to go to a business meeting and be tied up for hours. You actually do need to ask if he is able/available to ring back later.

Note: there is a subtlety in meaning between saying, 'Can/could you call me back..' and " 'Can/could you call back..'
The first adds a personal note to the conversation. The second, omitting the 'me', is what a receptionist would say when dealing with a call that another person is unable to take - less 'personal'. So, if you said, 'can you call back' when speaking to a friend, it sounds 'stand-offish', a little 'distant'.

[philadelphia]

So, dear boy, can't parlez vous at the moment.

I have ever seen it before but in my own language. Would you mind explaining this a bit more?

[awatef]

you can just say i'm driving right now i'll call you back later.

[monty mike]

I have ever seen it before but in my own language. Would you mind explaining this a bit more?

Sometimes english people throw french words into a sentence for fun.

[philadelphia]

Sometimes english people throw french words into a sentence for fun.

We do as well. Though "can't parlez vous" does not make sense in that case.

[monty mike]

We do as well. Though "can't parlez vous" does not make sense in that case.

No, because most english are crap at french.

[Soup]

There's also that button on your phone that moves in-coming calls to voice mail.

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Correction

How do you say ... ?

... when somebody calls me on my cell while I am driving, what is the most sophisticated way to say that I can't talk now?