SpeechScope:
    | "all"
    | "selection"
    | "left"
    | "right"
    | "group"
    | "parent"

How much of the formula should be spoken:

all the entire formula
selection the selection portion of the formula
left the element to the left of the selection
right the element to the right of the selection
group the group (numerator, root, etc..) the selection is in
parent the parent of the selection