I'm a researcher working with a language that has gone through phonological changes through time.  I would like to tag parts of a word (i.e. prefix, stem, suffix) and then apply those phonological changes and then see what is left or different about the stuff that I tagged.I'm currently using Python with some regex stuff to apply the changes so if I can do this using its NPL toolkit that would be perfect.  I've start to mess around with it but I haven't found anything that will work just yet.  I'm also not sure if this toolkit would be the best for this.For example, I apply the following transformation to tag re, peat and ed in repeated:$$\begin{align}  \mathtt{repeated}  & \xrightarrow{\mathtt{rep} \mapsto \mathtt{rp}} \mathtt{rpeated} \\  & \xrightarrow{\mathtt{ea} \mapsto \mathtt{e}} \mathtt{rpeted} \\  & \xrightarrow{\mathtt{d}\$ \mapsto \epsilon} \mathtt{rpete} \\\end{align}$$I would like to be able to find out what is left of the stuff I tagged.  So I'd like to see that r is all that is left of the prefix, pe is all that is left of the stem, etc.  Any help or direction is greatly appreciated!
Trying to tag parts of a word and keep track of any changes that happen to those parts
algorithms;strings;natural language processing;computational linguistics