Would this be allowed?
To some extent this seems unfair to allow. The main downside to Tongues seems to be that you can't understand people/communicate as well in times of stress. Deaf seems to incorperate that already with the being Deaf thing (can't hear them anyway). The only added downside is that you cannot communicate with them by talking yourself, which can be worked through by preperation in advance.
I remember someone mentioned that you cannot have a curse removed by any way and if you did, it would negate the oracles abilities (I wish I could quote where I saw that). I feel as if taking these two Curses negates the Tongues Curse.