Some good language identifiers include the one at Translated.net and the Rosette Language Identifier. One is free to the public to copy and paste online, while the other is a program to install on a computer.
At Translated.net, the language identifier takes text that is either copied and pasted into the program or typed into it. This program can recognize more than 70 languages, including Zulu, Welsh, French and Latin. Visitors to the website can see the translation in English, Italian or French.
The Rosette Language Identifier is a computer program that recognizes other languages in documents and other programs. This program tackles more than 180 language-encoding pairs and more than 50 languages.