The core Speck content management framework limits itself to content definition, storage, retrieval and display. It doesn't include features for managing site navigation or users, and doesn't have any tags for generating menus or pages. This is by design, and it means the core framework can be used to address content management requirements for a web site, without interfering with other elements.
The portal framework is a framework for building web sites with Speck at the core. We called it our portal framework because it evolved through our own use of Speck while building portal style sites (bit of a stupid name looking back at it now, but we're kinda stuck with it).
It uses content templates to generate content in different locations on a web site, and then wraps the generated content within a layout. A navigation tool allows administrators to build a site, deciding which template and layout combination is used at each location, and who can access and edit content at that location. A user management tool is included to manage access groups and administration roles.
The portal framework also adds tags for rendering breadcrumbs and menus (both used when creating layouts), a tag to maintain a content index (which can be used to build a search tool), and a built in file manager (a custom version of CF File Manager).
Using the portal framework is almost as simple as just switching from using the cf_spApp tag to cf_spPortal (you also need a portal config file and, although not strictly necessary, it's a good idea to create some templates and layouts).