Omission of the particle は


> 山本さん、会社を辞めるそうですよ。

In the sentence above there is no は after 山本さん.

Can we say `山本さんは会社を辞めるそうですよ`？

If we can, does the omission of は mean lack of formality?

I have come across another sentence similar to the one above:

> 田中さん、それからどうするんですか。（＝田中さん **は** それからどうするんですか。？）




In that case, there are two cases. One is omission of the particle は, the
other is just a call. You can judge it by the context. 山本さん、会社を辞めるそうですよ would
be the former case, but 山本さん、田中さんが会社を辞めるそうですよ is the latter case.

The omission of は in the former case is colloquial.




In that case, there are two cases. One is omission of the particle は, the
other is just a call. You can judge it by the context. 山本さん、会社を辞めるそうですよ would
be the former case, but 山本さん、田中さんが会社を辞めるそうですよ is the latter case.

The omission of は in the former case is colloquial.

