People who connect to the website don't need to know programming to access CGI programs. Instead, a programmer writes a CGI program. A number of languages can be used for CGI, such as C or C++, FORTRAN, Visual Basic, and AppleScript. An application written in a programming language such as C must be passed through a program called a compiler before it can be run. The compiler turns the application into a language CGI can understand. Other languages, called scripting languages, do not need to be compiled first. CGI scripts tend to be easier to debug, modify, and maintain than compiled programs so they are used more frequently. Perl is probably the most popular language used for writing CGI scripts.