Well, while the Observatory hasn't been able to translate any more utterances from the Dwellers, they haven't been completely idle! One thing they have been able to find out is that the Furthest Ring is the domain of the Aspect of nothingness, disappearance, and obscurity. Though naturally the Aspect is as difficult to find information on as the Dwellers within its domain, that could provide something of an explanation--there could be some kind of magical barrier to translation. Perhaps if you can gain the aid of the Dreamer linked to that Aspect, you'll be able to overcome it.