Comma after "Unfortunately" in the beginning of a sentence.

Here, Cambridge doesn't use a comma. I am confused. Example in Cambridge Dictionary: Unfortunately we can't come this evening after all.

https://dictionary.cambridge.org/de/worterbuch/englisch/unfortunately

On different pages i found some rules telling there needs to be a comma. Examples follow:

We do usually put a comma after adverbs like 'unfortunately'. They are called 'sentence adverbs' because they modify the whole sentence and often give the opinion of the speaker/writer.

A parenthetical phrase adding detail to the main clause. Initially placed parentheticals are normally set off by a comma.

Cause I'm studying for my Level 2 graduation, i want going crazy reading here and there comma rules followed by looking in the Cambridge Dictionary without finding them there.

HELP me out please !


The Oxford Manual of Style has this to say about sentence adverbs:

Adverbs and adverbial phrases that comment on the whole sentence, such as therefore, perhaps, of course, are often enclosed in commas, but this is not a fixed rule. Sense may be altered by the comma's placement or presence. Consider the following:

  • We'll go to Cornwall, perhaps in the spring. (perhaps then)
  • We'll go to Cornwall perhaps, in the Spring. (perhaps elsewhere)
  • Again she refused to speak. (once more)
  • Again, she refused to speak. (in addition)
  • The ship's captain ordered a change, of course. (indeed?)

In your particular example, the use of a comma would appear to be optional (and therefore a matter of style), since it doesn't alter the meaning.

  • Unfortunately we can't come this evening after all.
  • Unfortunately, we can't come this evening after all.

These both seem to mean the same thing, with a slight change of emphasis.