I don’t see why not. Marquesian is a language invented by Mathew Mercer as DM of the series Critical Role. It is an established language with a standard dialect and understood by speakers in a geographic region which seems to me that it fits the scope of a language. Within the Critical Role multiverse, Mercer allowed his players to use Comprehend Languages to understand Marquesian. So if characters in your setting or your DM use Marquisian, I think there is a strong case to be made that Comprehend Languages could be used.