Hall, 21, features at centre-half and was recently released by Sheffield United.
Akbas, a defensive midfielder, has credibility playing for clubs like Hull City as well as Antalyaspor and Boluspor before an ACL injury sidelined him.
Interim manager Jamie Yates said: “Ashton Hall is someone I’ve worked with before as a youth team player, he’s an excellent lad and a very good player. I’m looking forward to seeing him in a Sheffield FC shirt.
"Steve came to us through a contact of mine and has impressed in training, he’s coming back from a long-term injury but was previously pro in turkey.
"I am delighted to add them both to the squad."
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