ispell changed from emacs 24 to emacs 25, but how?

[djc]

I have some elisp code that relies on ispell (with hunspell) on Win7. It works 
under 24.5 and doesn't under 25.5 -- under 25.5, my code appears no longer to 
initialize some things that have to be set up, and documentation is scanty for 
what I have to initialize in ispell to be able to use it from other code. I 
wrote my own code mainly to do this setup, switching among multiple languages. 
It does nothing fancy.

Is there anyone who knows enough about ispell to give me some idea of what 
changed, and why, so I can adapt my code?  Although I've diffed the two 
versions and tried to make sense of the changes, I haven't yet been able to 
find what I have to do to make my own code work with the latest.

I want to use my code also on Linux, but I expect it to be relatively easy to 
adapt it once I have it going on Windows.

Tx

djc