Plugins provide functions that are associated with triggering events. Joomla provides a set of main plugin events, but any extension can trigger (custom) events. Joomla Modules are usually small pieces of functionality designed to present information on your site. They can appear several times, on several pages in different positions.
The components are usually the most complex and could be considered as an applet, for example, templates control the design of your site, what visitors see when they arrive at your website. There are no examples of this type in Joomla Core and it is the least used, however, it can be used, for example, to place CLI scripts in the cli directory within Joomla or to place template overrides in a specific directory. Many of the most popular third-party extensions in Joomla use libraries to reuse common functions in all their components. Once again, there are core plugins and plugins that are configured in Joomla as part of the installation of third-party components.
Modules are one of the simplest parts of Joomla and a great entry point for people learning to use the system (the equivalent of widgets in wordpress). Creating a simple module for Joomla is one of the simplest development steps you can do, and the simple module creation tutorial is designed to guide you through this. On the other hand, a Joomla component is usually more complex, with extensive functionality and capabilities. You can install from the Joomla Extension Directory (Install from the Web), upload an extension, install from a folder, or install from a URL.
These are all different types of Joomla extensions, or plugins that create and adapt to specific Joomla features or functions. In Joomla many language packs are installed as a package so that the frontend and backend languages can be installed independently.