Variable
ConstNamed rather than indexed, because it is not the first or the last of SEEK_STEP_OPTIONS_SECONDS but a choice of its own: five seconds is the length of a spoken phrase, which is what the gesture is for here — the learner missed a sentence, not a chapter. The shorter interval is there for a single word or sound, and the longer one for a paragraph.
The step a learner who has never chosen gets, in seconds.