Can the tongues spell decipher writing (directly or indirectly)?

The description for tongues states,

This spell grants the creature touched the ability to speak and understand the language of any intelligent creature

It makes no special mention of understanding written languages–just that you can “understand the language”. If it doesn’t include this ability, though, could, for example, a Dwarf using the spell read aloud a message written by Orcs (since apparently Dwarvish and Orcish use the same writing system, but if that’s not how the actual languages in the settings work then replace the example with languages that do work that way), and then listen to and understand their own Orcish?