Answer: "Regrettable" versus "regretful" and "regrettably" versus "regretfully."

[achacunsagloire.livejournal.com]

Our next question comes from srsly_yes, who would like to know:

When do you use “regrettable” versus “regretful” and “regrettably” versus “regretfully”?

( An excellent question, srsly_yes, and one whose answer we must regretfully venture into the sleepy town of Silent Hill in order to find... )