Programming languages do not provide in general facilities which allow for usage of routine libraries written in other languages. Usually this facility (when provided) is realized by a linking utility program which does not know the characteristic features of the languages involved in the linking process. The programming language LL provides a mechanism which allows for disciplined access to external libraries written in another language. This mechanism was designed so that external libraries can be used in an object-oriented way, even when they were not originally designed as such. LL doesn't have primitive data types (integer, boolean, real, etc). These data types as well as user-defined data types can be tailored for specific needs of specific user communities.