Re: ispell language per buffer, not for all buffers

[Richard Stallman]

    This isn't currently possible, since there's only one Ispell process,
    and changing a dictionary requires restarting the Ispell program.

Restarting Ispell if it was last used with a different dictionary does
not seem too hard, and should be reasonably efficient most of the
time.

    To implement something like what you want, there's a need for a
    separate Ispell process for each buffer.  I agree that it would be
    a useful feature.

That seems like a wasteful implementation in comparison with the
other one above.