The weave of magics has been revealed to you through reading Taitus' equations and you took something with you.  You now have the ability to cast Speak with Dead as a ritual spell, once per Long Rest and casting the spell in this way does not consume a spell slot.  You regain the use of this ability at the end of a Long Rest.

A wizard spell on a spell scroll can be copied just as spells in spellbooks can be copied. When a spell is copied from a spell scroll, the copier must succeed on an Intelligence (Arcana) check with a DC equal to 13. If the check succeeds, the spell is successfully copied. Whether the check succeeds or fails, the spell scroll is destroyed.

Notes: Utility, Consumable