Okay, yes, David is a robot with amazing languages skills, BUT there is NO way to determine the sound of a language solely via its text.
No matter how many intelligent algorithms, CPU power, etc you have, its just not possible!
Example: Today, we have no clue exactly how Latin sounded! And we understand the language 100%. Now David, using a language he might not even fully comprehend, somehow determined how to speak it? Ya, not possible. Furthermore, he did not have nearly a large enough sample size from the small conversation he heard in the hologram if that was even a conversation.