Yes, a seer can know these languages. The (otherwise) secret tongue of the Dwarves is called Khuzdul. The doggerel tongue of the Orcs is called TheBlack Speech (and Goblin and Orc are synonymous).crusssdaddy wrote:Can my Seer have Dwarf and Goblin as two of his languages? If so, what are the proper names for those? And is the 'Northern Tongue' a language that would be appropriate for someone from the former Kingdom of Arnor?
The Northern Tongue is probably a dialect of Westron; a more ancient form. Yes, it was formerly spoken in Arnor.
See here http://www.uib.no/People/hnohf/www.uib.no/People/hnohf/ for many other language options (and check the Mannish Tongues link too).