[Aila's a shitty theorist, but legitimately an accomplished practical mage in a couple of schools, so she can certainly talk shop.]

Conjuration school.

[Apparently she's going to discuss magic with weird strangers in the middle of the woods. Sure.

Aila leans back on her elbows, looking out over the stream and holding one hand palm up. It starts to dance with purple-black magical energies as she readies Soul Trap.]

When the soul departs the body, the spell blocks it from crossing to Oblivion or Aetherius and channels it into a soul gem instead.

Far as I know, soul gems are naturally occurring, though I've only seen one place you can mine them. A talented enchanter might be able to create artificial ones, maybe.

[She shrugs the shoulder not connected to the arm with the Soul Trap spell at the end of it. No one would ever describe her as more than an "acceptable" enchanter.]

Any fool can use a weapon enchanted with Soul Trap, but you need training to cast the spell. Not much training, though.

[Since she doesn't plan on capturing any souls right this second, Aila lets the spell die uncast, and the eerie light fades rapidly to nothing.]