It is very unlikely for a "common spoken language"---which is also within general every-day use---to develop in any continent, or world.
Far more likely is that a non-verbal "trade language" would develop, which would see use mainly when different peoples came together to trade goods, on the pattern of the Native American "world." This "trade language" had been developed to be non-verbal, to get past how nuances of pronunciation, one language to another, would render many spoken words very difficult if not impossible to understand, when pronounced by persons of different tribes.
The "Native American sign language" had evidently come about as a trade language, originally, and very early narratives by Caucasian explorers had often remarked how persons from tribes whose "ranges" were separated not only by hundreds of miles, but also in many cases by physical barriers such as the Mississippi river, or areas under control of hostile tribes, had been able to communicate with one another by "signs."
The Caucasian observers had often viewed the use of a sign language as amazing; virtually bordering on "magic," in some cases. Their initial amazement and even misgiving hadn't interfered with their eagerness to adopt the new sign-language, however!
"Indian signs" had no nuances of pronunciation, such as are seen when comparing many, many modern examples---there are vast differences in word-pronunciation when comparing Northern vs. Southern states; those Eastern vs. Western regions; the Left-Atlantic vs. Right-Atlantic countries; and even those Northern-Hemisphere vs. Southern-Hemisphere countries.
Most of these differences in English pronunciations also exist at a time of major trade and human inter-action; when it's common for people to hear, see, and often even befriend, speakers from other areas. With so much inter-regional communication going on, one might assume people would work actively to minimize pronunciation differences. Instead, the opposite seems the case, with people celebrating the "roots," and the "heritage," of their different areas-of-birth.
The same great differences in pronunciation are evident in other languages that have now grown to span oceans. At times, it's extremely difficult for an "Old World" speaker to understand what's being said by a "New World" speaker, and there are no signs that any steps are being taken to make the "dialects" easier to understand.
Modern onlookers must not imagine that "Indian sign language" was in any way inferior to a spoken tongue: Complex thoughts could be communicated; not merely information relating to the various quantities and relative values of goods.
It also showed the ability to very rapidly evolve, as seen by the speed by which signs had been created, and had evolved, to include new-comers, (such as Caucasians) and Christian clergy; and to include new Caucasian technologies, such as firearms and ammunition.
The same general "evolution" of a sign-language to take the place of a spoken dialect to allow foreigners and traders to communicate with far-flung peoples has been seen in South America, along the Amazon.
The development of similar sign-languages had been seen in other places where traders or explorers had sought to communicate with widely-separated tribes of groups of people---Africa is the most obvious example, but similar use of sign-languages had been seen along the various island-chains in the Pacific--
space does not allow detailed investigation.
In the end, vagaries of pronunciation effectively rule out there being the evolution of any SPOKEN "trade-language" on such a world.
It would be extremely unlikely for distantly-related "races" or "species" such as "Humans" and "Dwarves" to share very much of a language-base, as well! At one time, there had been well over a hundred Native American "Tribes" on the Continent, and there had been dozens of "Tongues" that were shared by many (BUT NOT ALL!) tribes, within an "alliance," or "Confederation." This was the case, world-wide.
We have no blueprint for any single wide-spread language existing. Historically, it was the case that community leaders---shamans or chiefs---would be fluent in two to four regional languages: Those languages of their own tribe, plus brother-tribes or sister-tribes, of applicable; plus the languages of the neighboring tribes . . . who were often counted as their foes, unfortunately.
A Shaman or Chief might be fluent in half a dozen languages, but this would probably not "get him very far" so to speak, on the ground.
That is why many, if not most, members of almost every tribe in North America were fluent in "Sign Language."