About parser parameters informs you that GuessRoots is one of the parameters you can select in the Parser Parameters dialog box.
About the Novel Root Guesser provides an overview of the Novel Root Guesser feature.
If you will use the Hermit Crab (HC) parser to guess roots, you will need to create one or more pattern-matching entries. If you have not created at least one pattern-matching entry, then root guessing will not happen even when GuessRoots is selected.
Create a lexical entry with a Lexeme Form that is a pattern constructed from natural classes.
Then, that entry is used as a pattern-matching entry by the root guesser.
You can create the pattern from any natural class that is defined in the Natural Classes tool (Grammar).
If you need to refer to "any possible character", you can create a natural class for that. For example, you might create a natural class based on features, name it Segment, with the abbreviation Seg, and define it as having the feature Seg:+
When constructing a pattern in an entry, the elements you can use are:
A natural class will match any single character in that natural class. Examples: [C][V] or [Seg]
A * means zero or more of that natural class. Examples: [Seg]* or [C][V][C]*
Parentheses around a natural class means optional. Example: [C]([C])[V]
When you create these entries, create a separate entry for each category that you want the root guesser to guess.
You may also add inflection classes, inflection features, or stem names if those are part of the constraints for roots of this category. Create a separate entry for each possibility that should be guessed.