You've received a document or purchased an exotic book and are stumped as to what language it is written in. You can determine what language your book or document is written in if you have patience and are willing to do a bit of research. You can also find an interpreter that will be able to help you discern the language and meaning of the item you are examining.
Call the language department of the local university and ask if you can fax over the document or a copy of a few pages to the department. Ask if they would be willing post a copy of your item on the faculty or graduate bulletin board with your name, number and the offer of compensation to anyone who can help you narrow down the language you are seeking. Most departments are happy to list your work in order to help graduate students or faculty obtain a little extra cash.
Call a local rare bookseller. Some have come across just about every language in print and may be able to help you determine the language. University libraries can also help you, particularly if they are known for a specific type of collection that would take in copies from all around the world. For example, if they have a children's book collection, chances are they have children's books from all over the world and are used to determining languages. Take the book or document to the bookseller or library in person and ask for assistance.
Call the local department of education and ask if you can obtain the email or extension of the ESL (English as a Second Language) instructor. Many of these instructors come across dozens of languages in the course of their daily work and may be able to help you determine the language. They may even arrange for you to have a translation done by one of their students. This also goes for the local ESL graduate studies program at your local university.
Submit your document to an online translation service, one that has a broad array of languages at its command such as Freetranslations.com, Word Lingo, and Translated.net. For a fee, these services will translate your document for you.
Scan the document into your computer, then copy and paste characters into a search engine that is specially designed to translate documents and identify languages. Google Language Detection, What Language is This and Polygot 3000 are three popular language detectors on the internet.