The Library has a special section of books called the Reference Collection, which contains specialized encyclopedias and dictionaries on every discipline, including Linguistics.
Reference books can't be checked out, but you're welcome to use them in the Library and take scans of the parts you need for your research.
Reference books on this guide have the 
icon next to them.
The Reference Collection is the first set of book stacks beyond the open computer area.
There is a whole shelf dedicated to Linguistics
Ethnologue is one of the most authoritative resource on world languages and is a required resource for your project
Ethnologue is published in 3 volumes, organized by region:
Within each volume, entries are organized by subregion and country (not by language or language family), so its important to have an idea of where your chosen language is spoken.
Language entries in Ethnologue always include the same components:
Here's an example:
If you need help, each volume has several indexes in the back to help you locate your specific language, including:
