No, not by (for example) typing on the keyboard. Any kind of single-stroke text that you create (either by capturing handwritten text or using Hershey Text) is actually a set of _paths_. You _can_ edit those paths by using the various path editing tools ink Inkscape. However, there is no text there that could be edited.
If you want to use regular fonts, then they can be edited just fine, but you still need to convert them to outlines before plotting.
