Yes, the Raven can speak with everyone (in common), but starting at first level, not fifth.
As you quoted it, the Raven obtains a supernatural ability which will allow it to speak one language.
This feature has no relation with Speak with Master, obtained at fifth level.
Speak with Master :
If the master is 5th level or higher, a familiar and the master can communicate verbally as if they were using a common language. Other creatures do not understand the communication without magical help.
Therefore, at fifth level, in addition to being able to speak with everyone in common, the Raven will also be able to speak with his master, but with a language understandable only for both of them.