Most user workstations only need to support one language. All that is needed when an ESL program is installed for the user is to install the proper external string resource DLL.

When a single workstation needs to support more than one language, then one DLL for each language is installed. If the language to be used is known when the program is started, perhaps by user configuration information or by choosing the correct icon, then pass the name of the proper DLL to the runtime. See Runtime Switches.

There are some applications that need to change the language that is displayed to the user while the program is running. For example:

•A program to provide information to the public, where each user could select the language they wish to use.

•A program which is used by a multi-lingual user, such as a customer service representatives. They could change the language according to the language used by the person they are speaking to.

•Within a single language, external strings can be used to switch prompts and descriptions between a verbose "new user" version and a terse "experienced user" version.