I read over the oracle's Deaf curse and though it says your deaf it doesn't say your mute. You are giving the Silent Spell feat to take out the 20% spell failure chance on spells with verbal components.
I would take a guess that this curse would be treated as if you were profoundly deaf in the real world, and I would like to point out that most deaf people can speak. The speech of a deaf person has different ranges, some being very difficult to understand and others being almost better then some hearing people. So for the purpose of role playing you still have the ability to be verbal. However most deaf people don't like speaking because they don't know how they sound.
Though this isn't helpful in combat, it can help roleplay.
I would say for anyone trying to understand what a deaf person is saying it would be a linguistic skill check on the part of the deaf person about how well they can speak. DC depends on language for example common language and their native racial language could be DC 5 and many other racial languages like Elven or Dwarven if not native could be DC 10 things like Celestial or Abyssal could be DC 15 and anything like undercommon or languages that are mixes as DC 20. Base all DC's on the relevance of the language to the character. Same with speech reading.
However...
Requirements:
They must know the language spoken to speech read or speak it.
+2 ranks in Linguistics
Must be face to face no more than 5 feet apart for speech reading
Concealment of any kind negates ability to speech read but not speak
If 20+ feet away DC's are higher (deaf don't know volume of voice) for speaking
If all else fail BUY CHALK AND A CHALK BOARD!!!!!! They are cheap I think 1 copper per chalk piece and 1 gold for the board. In real life you can use a small dry erase board or just talk it out as if you were writing it.
Drawing can be fun for role play especially if you can't draw in real life very well.