<s>
Ispell	B-Application
is	O
a	O
spelling	B-Application
checker	I-Application
for	O
Unix	B-Application
that	O
supports	O
most	O
Western	O
languages	O
.	O
</s>
<s>
It	O
offers	O
several	O
interfaces	O
,	O
including	O
a	O
programmatic	O
interface	O
for	O
use	O
by	O
editors	O
such	O
as	O
Emacs	B-Application
.	O
</s>
<s>
Unlike	O
GNU	B-Language
Aspell	I-Language
,	O
ispell	B-Application
will	O
only	O
suggest	O
corrections	O
that	O
are	O
based	O
on	O
a	O
Damerau	O
–	O
Levenshtein	O
distance	O
of	O
1	O
;	O
it	O
will	O
not	O
attempt	O
to	O
guess	O
more	O
distant	O
corrections	O
based	O
on	O
English	O
pronunciation	O
rules	O
.	O
</s>
<s>
Ispell	B-Application
has	O
a	O
very	O
long	O
history	O
that	O
can	O
be	O
traced	O
back	O
to	O
a	O
program	O
that	O
was	O
originally	O
written	O
in	O
1971	O
in	O
PDP-10	B-Device
Assembly	B-Language
language	I-Language
by	O
R	O
.	O
E	O
.	O
Gorin	O
,	O
and	O
later	O
ported	O
to	O
the	O
C	B-Language
programming	I-Language
language	I-Language
and	O
expanded	O
by	O
many	O
others	O
.	O
</s>
<s>
The	O
generalized	O
affix	O
description	O
system	O
introduced	O
by	O
ispell	B-Application
has	O
since	O
been	O
imitated	O
by	O
other	O
spelling	B-Application
checkers	I-Application
such	O
as	O
MySpell	B-Application
.	O
</s>
<s>
Like	O
most	O
computerized	O
spelling	B-Application
checkers	I-Application
,	O
ispell	B-Application
works	O
by	O
reading	O
an	O
input	O
file	O
word	O
by	O
word	O
,	O
stopping	O
when	O
a	O
word	O
is	O
not	O
found	O
in	O
its	O
dictionary	O
.	O
</s>
<s>
Ispell	B-Application
then	O
attempts	O
to	O
generate	O
a	O
list	O
of	O
possible	O
corrections	O
and	O
presents	O
the	O
incorrect	O
word	O
and	O
any	O
suggestions	O
to	O
the	O
user	O
,	O
who	O
can	O
then	O
choose	O
a	O
correction	O
,	O
replace	O
the	O
word	O
with	O
a	O
new	O
one	O
,	O
leave	O
it	O
unchanged	O
,	O
or	O
add	O
it	O
to	O
the	O
dictionary	O
.	O
</s>
<s>
Ispell	B-Application
pioneered	O
the	O
idea	O
of	O
a	O
programming	B-Application
interface	I-Application
,	O
which	O
was	O
originally	O
intended	O
for	O
use	O
by	O
Emacs	B-Application
.	O
</s>
<s>
Other	O
applications	O
have	O
since	O
used	O
the	O
feature	O
to	O
add	O
spell-checking	B-Application
to	O
their	O
own	O
interface	O
,	O
and	O
GNU	B-Language
Aspell	I-Language
has	O
adopted	O
the	O
same	O
interface	O
so	O
that	O
it	O
can	O
be	O
used	O
with	O
the	O
same	O
set	O
of	O
applications	O
.	O
</s>
<s>
There	O
are	O
ispell	B-Application
dictionaries	O
for	O
most	O
widely	O
spoken	O
Western	O
languages	O
.	O
</s>
<s>
Ispell	B-Application
is	O
available	O
under	O
a	O
specific	O
open-source	O
license	O
.	O
</s>
