pg_language
   The catalog pg_language registers
   languages in which you can write functions or stored procedures.
   See CREATE LANGUAGE
   and Chapter 42 for more information about language handlers.
  
Table 53.29. pg_language Columns
Column Type Description  | 
|---|
        Row identifier  | 
        Name of the language  | 
        Owner of the language  | 
        This is false for internal languages (such as SQL) and true for user-defined languages. Currently, pg_dump still uses this to determine which languages need to be dumped, but this might be replaced by a different mechanism in the future.  | 
        True if this is a trusted language, which means that it is believed not to grant access to anything outside the normal SQL execution environment. Only superusers can create functions in untrusted languages.  | 
        For noninternal languages this references the language handler, which is a special function that is responsible for executing all functions that are written in the particular language. Zero for internal languages.  | 
        This references a function that is responsible for executing “inline” anonymous code blocks (DO blocks). Zero if inline blocks are not supported.  | 
        This references a language validator function that is responsible for checking the syntax and validity of new functions when they are created. Zero if no validator is provided.  | 
        Access privileges; see Section 5.7 for details  |