<p>The basics have already been answered <a href="https://stackoverflow.com/questions/257125/human-language-of-a-document">here</a>. But is there a pre-built PHP lib doing the same as Lingua::Identify from CPAN?</p>

There's a PEAR package
```
Text_LanguageDetect
```
that I've used before. Get's the job done well enough. I'm not sure of any other libs that are more mature.