Graphical representations of taxonomies

 
Figure 3: A basic system design taxonomy 

 
Figure 4: A basic corpus design taxonomy 

 
Figure 5: A basic lexicon development taxonomy 

 
Figure 6: A basic language model taxonomy 

 
Figure 7: A basic physical characterisation taxonomy 

 
Figure 8: A basic assessment methodology taxonomy 

 
Figure 9: A basic speaker recognition taxonomy 

 
Figure 10: A basic speaker verification taxonomy 

 
Figure 11: A basic speech synthesis taxonomy 

 
Figure 12: A basic interactive systems taxonomy 

The sub-taxonomies for different areas show very different kinds of structure, as to be expected. The differences encompass the following topological and semantic features of the graphs which are, with few exceptions, tree graphs:

• Number of nodes.
• Depth of branching.
• Breadth of branching.
• Differences in node interpretation, e.g. in terms of formalism (notation, terminology, nomenclature), empirical method, or sub-domain (field, subject).
• Differences in edge interpretation, e.g. as is-a or strict taxonomic interpretation, vs. part-of or mereonomic interpretation.

However, the explicit graphical representation of the taxonomies provides a useful basis for future work, in which similarities between the different sub-taxonomies can be examined in more detail and, in some cases, merged.