The Umbrella Academy: 10 Huge Questions For Season 2
9. Will Allison Get Her Voice Back?
If Allison can be brought back to health after having her throat slit, it should be possible for her to also reclaim her voice.
In the comics, it didn't take too long for the character to be given some new vocal chords, with the Temps Aeternalis (the name of The Commission in the books, one of the many changes the show made) having their surgeons fix them on the order of Number Five, so it's not like giving the character back her ability to speak would be a deviation from the source material.
Also, if Hargreeves could construct an entire person, then there's likely someone other than The Commission in Netflix's Umbrella Academy universe that can help Allison in this matter.
Plus, if not, then time travel is always an option (they're using it to solve all of their problems anyhow).