Nofri Remenkimi, I recently came across some of recordings (including Coptic lessons and hymns) made by Fr Shenouda Maher (formerly Dr Emile Maher) teaching/employing the Old-Bohairic pronunciation available online at:
http://www.rochcopts.org/CopticTeachingTapes.php <http://www.rochcopts.org/CopticTeachingTapes.php> The text from some of the lessons can be found here: http://www.coptic.org/language/emilmaher/ <http://www.coptic.org/language/emilmaher/> Oudjai, Ambrose.