Joycelyn is quite the mixbag of accents. Raised on Panatha, one would think she has something of a Turkish accent like Darth Vornskr, but she grew up speaking the language of the Vahla to her mother and sister, which is more like Welsh. Vahlan was the "low" form, while Epicant was the "high" form. Meaning, she would speak Epicant in public and Vahlan (what I choose to call the Vahla Language) in certain circles, or sometimes mixing the two into a sort of pidgin. She would have some accent in both, but very faint as she would grow up effectively bilingual.
Her Galactic Basic would be of Imperial format with a stronger presence of Vahlan accent than Epicant. For Imperials who speak Vahlan, the Epicant element would be difficult to place, but present. Some would perhaps think it's a speech impediment or dialectal feature.
As for my Darth Ophidia, she used to have an accent, like a hard version of a latin-based language. However, she shed it for Imperial Basic (English Received Pronunciation), and to be honest, sounds kind of posh.