Now, we can use

[Rachel Adams]

This question was answered on WR but not by a teacher/native speaker. I wanted to know a teacher's opinion.
I can't provide the link, but the name of the thread is "now, we can use".

(Link = https://forum.wordreference.com/threads/now-we-can-use.3931793/ - 5jj)

Should there be a comma after "now"?
I checked my dictionary and saw that when it's at the beginning of a sentence it's sometimes used with a comma. Should I use it in my sentence too or is it optional?

"Now, we can use computers in any language."


Examples from the dictionary.

Now, listen to what she's saying.
Now, the next point is quite complex.
Now come and sit down.
Now let me think.

 

[jutfrank]

It all depends on what you mean. Either give us some context or tell us what the word Now means in your sentence. Are you trying to use it in the sense of 'nowadays'?

 

[Rachel Adams]

It all depends on what you mean. Either give us some context or tell us what the word Now means in your sentence. Are you trying to use it in the sense of 'nowadays'?

Yes, I mean 'nowadays'. If I mean "nowadays" should it be used with a comma?

 

[jutfrank]

Yes.

 

[Rachel Adams]

Yes.

But is there a comma in these examples?
Now, listen to what she's saying
Now, the next point is quite complex
Now come and sit down
Now let me think....

I mean in this kind of examples when is it optional? For example, can I use it in the last two sentences and remove it from the first two sentences?

 

[jutfrank]

It depends on the particular use of the word now.

If the use is to connect logically to a previous sentence, no comma is used:

Put your glasses on. Now you can see.

In the sentence above, Now has a resultative meaning. It has a logical connection to the previous sentence. Similarly, when the word has a the sense of saying what happens next, there should also be no comma:

Now come and sit down.

But when the word means 'nowadays', use a comma. Equally, when the word is a discourse marker signally to the listener that the discourse is moving in a new direction, then a comma (which replaces a pause in speech) is very useful:

Now, the next point is very complex.