punctuation with hi/hello and the direct address
 

I am teaching my students to write letters now. Explaining some cases of punctuation, I say that they should write
- Hello, Mike,
- Hi, Kate,
- Good morning, Mister Smith,
- How are you, Toni,
I explain that we always use a comma when directly addressing someone/something, regardless of whether the direct address is at the beginning or end of the sentence. If the direct address is in the middle of a sentence, we use a pair of commas to set off the direct address.

But, I often receive emails (from native speakers) that begin "Hi Tania," or "Hello Tania,".

So, what is the correct punctuation? What should I teach my students?

I do appreciate your help.

Re: punctuation with hi/hello and the direct address
 

Hi Tania,

There's no comma after [i]Hi/Hello/Dear/Good morning + name + commain the opening salutation of an e-mail. The only exception might be if Good morning + name were followed by an exclamation mark : Good morning, Tania! would be possible, though personally I'd still prefer to exclude the comma even in this case.

Notice that Mr. is always abbreviated in English (as are Mrs and Ms) - never written fully as you have done in your message. Also, if you are using title + surname, then the relationship must be neutral if not completely formal. So I would use Dear... rather than the others. The only exception might be if the relationship was eg. teacher/school student, where the title+surname are conventionally used to show respect but the relationship may actually be quite close.

So, I would expect :

Hi Tania,
Hello Tania,
Good morning Tania,
Good morning, Tania!
Dear Tania,or

Dear Mrs. Smith,
Dear Ms. Smith,

and only in the case of a close but conventionally respectful relationship :

Good morning, Mr. Smith!

Hope that helps.
Sue

Re: punctuation with hi/hello and the direct address
 

Thank you. It does help.