The modern construction would be something like:
- Is not heard anymore, or
- Is no longer heard
The main difference being that in Shakespeare the negative is placed after the verb: 'heard not' instead of 'not heard'.
We still occasionally use 'verb no more' constuctions such as 'we can do no more', 'we can give no more', and so on—but it's more common in Shakespeare.
Part of the reason might be that it was a more common construction at the time, but another reason is—once again—the rhythm.
- 'No MORE' = da DUM
- 'Is HEARD no MORE' = da DUM da DUM.
