Trying to fit Miss Spell's powers into neat classifications based on scientific principle is impossible, because for her, scientific rules simply don't apply.  What exactly the limits of her powers are is unknown, except that she can only alter reality or cause a desired effect by speaking a keyphrase and knowing precisely what result she hopes to achieve.  Put simply, if Miss Spell can envision it, and then articulate it, then within reason, she can cause it to happen.

The happenstance of her magic is that any effect she wishes to have happen must be accompanied by gestures and spoken in a garbled tongue that to the eye appears to be phonetic, anagramic, dyslexic, or a combination thereof.  Simplistic magic, that which only affects herself or one person, ordinarily only requires a single spoken word or short phrase of her magical tongue ("Carpit" to change a person into a rug, "Trann Sporte" to teleport herself to a location).  More complex magic-- the sort which would affect otherplanar creatures, people with defenses against magic, a far greater number of people, or which might cause larger 'ripples' of reality-- often requires her to recite much more complex incantations ("Distroy tha feind hoo seaks too a-tac mee.").  In addition to her spellcasting ability, Miss Spell is well-read on magic, mysticism and things arcane-- quite possibly perhaps as much as... or more than... any human who fights on the side of good.

If there are any flaws to her spellcasting, it tends to be problematic if she cannot speak or is in some way incapacitated, either physically or vocally, obviously.  Other than that, she is still relatively new to her position, and as such, has been taken unaware on occasion by threats that she hasn't recognized.
 

The woman who now calls herself Miss Spell is the latest in a long-standing order of magi known collectively as the Defenders of Magic, who have helped to protect their own lands and the world, overall, for centuries.  The Defenders of Magic have safeguarded Earth from magical threats and entities, and have served as diplomats to the various hosts of Chaos and Order, to keep the balance from skewing too much in one direction or the other.  Very little is known about the Defenders, except that they have been around for almost as long as human reckoning, and that their secrets are ordinarily passed down from one magus to their sole apprentice, who ordinarily serves for a period of no less than twenty years before such a grandiose position can be conferred onto them.

Emily MacEwan, a Defender from Wales who dubbed herself Madam Arcanus, had no such luxury when her time came to pass beyond.  Knowing a duel between herself and an otherplanar daemon would likely be her last, she still considered herself well-prepared to pass on her legacy.  She'd spent thirty-two years training her own apprentice, Fredek, to succeed her, after all.  The daemon outplanned her, though-- while Madam Arcanus prepared herself for her duel in her sanctum, two of its minions attacked Fredek, and ripped his soul free of his body, leaving nothing but a useless, unliving shell.

The now-desperate Madam Arcanus sought a worthy successor as her time neared, and found someone in a young history and antiquities student in Hub City named Trysta Vale, who dabbled in Wicca, Enochian theory and Crystallomancy.  Bringing Trysta to her sanctum through the veils of magic, she explained that Trysta had a destiny that she would help her attain for as long as she could.  Trysta then got a twenty-year course of apprenticeship compressed into a matter of weeks, learning the basics of focusing and channeling power through a chosen spoken phrase.  The rest she would have to learn through bookstudy, as Arcanus never returned from her duel. 

Over the course of the next few years, the newly-dubbed Miss Spell decided that she just couldn't be holed up in the Sanctum in a foreign country forever, and chose to move the sanctum back to her home-- an act that, like her pun-like chosen name, and her costume, she was sure Madam Arcanus wouldn't wholly approve of. 

Despite those liberal-minded changes, Emily could not have hoped to choose a better successor, all the same.  Not only did the thought of making real, visible, palpable magic rather than the more faith-oriented and vague New Age magick spur her on, but Trysta was a serious-minded and very responsible young woman, as well, and took her new title of Defender of Magic with great gravity.  That didn't stop the first few years from being extremely harrowing, however.  The resettling of the sanctum into Hub City itself proved to be a challenge to her.  And when she fought her first major disturbance in her hometown, she needed help from some of Hub City's other heroines, which led to the formation of the Justice Friends.  She's fought a heated internal battle with herself over whether the heroine that protects Hub City should be more important than the mystic who constantly studies to better herself as a Defender of Magic.

Although she is a Justice Friend and a well-respected heroine in Hub City, Miss Spell tends to keep to herself when she is not fighting crime.  In some respects, she can be a little unnerving to other heroines, partially because she has a constant aura of sheer unknowability that just tends to surround her due to her mystical nature, and partially because she's waffled back and forth on whether stopping simple crimes like bank robberies are beneath the importance of her station.  A few who don't know her well might consider it haughtiness.  But in truth, it's a facet of herself that Trysta has to wrestle with almost daily.