About Hunspell

Hunspell is a free spell checker and morphological analyzer library and command-line tool, licensed under LGPL/GPL/MPL tri-license.

Hunspell is used by LibreOffice office suite, free browsers, like Mozilla Firefox and Google Chrome, and other tools and OSes, like Linux distributions and macOS. It is also a command-line tool for Linux, Unix-like and other OSes.

It is designed for quick and high quality spell checking and correcting for languages with word-level writing system, including languages with rich morphology, complex word compounding and character encoding.

Hunspell interfaces: Ispell-like terminal interface using Curses library, Ispell pipe interface, C++/C APIs and shared library, also with existing language bindings for other programming languages.

Hunspell’s code base comes from OpenOffice.org’s MySpell library, developed by Kevin Hendricks (originally a C++ reimplementation of spell checking and affixation of Geoff Kuenning’s International Ispell from scratch, later extended with eg. n-gram suggestions), see http://lingucomponent.openoffice.org/MySpell-3.zip, and its README, CONTRIBUTORS and license.readme (here: license.myspell) files.

Main features of Hunspell library, developed by László Németh:

Unicode support
Highly customizable suggestions: word-part replacement tables and stem-level phonetic and other alternative transcriptions to recognize and fix all typical misspellings, don’t suggest offensive words etc.
Complex morphology: dictionary and affix homonyms; twofold affix stripping to handle inflectional and derivational morpheme groups for agglutinative languages, like Azeri, Basque, Estonian, Finnish, Hungarian, Turkish; 64 thousand affix classes with arbitrary number of affixes; conditional affixes, circumfixes, fogemorphemes, zero morphemes, virtual dictionary stems, forbidden words to avoid overgeneration etc.
Handling complex compounds (for example, for Finno-Ugric, German and Indo-Aryan languages): recognizing compounds made of arbitrary number of words, handle affixation within compounds etc.
Custom dictionaries with affixation
Stemming
Morphological analysis (in custom item and arrangement style)
Morphological generation
SPELLML XML API over plain spell() API function for easier integration of stemming, morpological generation and custom dictionaries with affixation
Language specific algorithms, like special casing of Azeri or Turkish dotted i and German sharp s, and special compound rules of Hungarian.

Main features of Hunspell command line tool, developed by László Németh:

Reimplementation of quick interactive interface of Geoff Kuenning’s Ispell
Parsing formats: text, OpenDocument, TeX/LaTeX, HTML/SGML/XML, nroff/troff
Custom dictionaries with optional affixation, specified by a model word
Multiple dictionary usage (for example hunspell -d en_US,de_DE,de_medical)
Various filtering options (bad or good words/lines)
Morphological analysis (option -m)
Stemming (option -s)

See man hunspell, man 3 hunspell, man 5 hunspell for complete manual.

Translations: Hunspell has been translated into several languages already. If your language is missing or incomplete, please use Weblate to help translate Hunspell.

Dependencies

Build only dependencies:

g++ make autoconf automake autopoint libtool

Runtime dependencies:

	Mandatory	Optional
libhunspell
hunspell tool	libiconv gettext	ncurses readline

Compiling on GNU/Linux and Unixes

We first need to download the dependencies. On Linux, gettext and libiconv are part of the standard library. On other Unixes we need to manually install them.

For Ubuntu:

sudo apt install autoconf automake autopoint libtool

Then run the following commands:

autoreconf -vfi
./configure
make
sudo make install
sudo ldconfig

For a non-root install, use DESTDIR so libtool skips ldconfig:

make install DESTDIR="$HOME/hunspell-root"

For dictionary development, use the --with-warnings option of configure.

For interactive user interface of Hunspell executable, use the --with-ui option.

Optional developer packages:

ncurses (need for –with-ui), eg. libncursesw5 for UTF-8
readline (for fancy input line editing, configure parameter: –with-readline)

In Ubuntu, the packages are:

libncurses5-dev libreadline-dev

Compiling on OSX and macOS

On macOS for compiler always use clang and not g++ because Homebrew dependencies are build with that.

brew install autoconf automake libtool gettext
brew link gettext --force

Then run:

autoreconf -vfi
./configure
make
sudo make install

Compiling on Windows

Compiling with Mingw64 and MSYS2

Download Msys2, update everything and install the following packages:

pacman -S base-devel mingw-w64-x86_64-toolchain mingw-w64-x86_64-libtool \
          mingw-w64-x86_64-libiconv mingw-w64-x86_64-gettext

Open Mingw-w64 Win64 prompt and compile the same way as on Linux, see above. Without mingw-w64-x86_64-libiconv the build still succeeds but the hunspell tool cannot convert between dictionary encodings, so any test or dictionary that declares a non-UTF-8 SET (e.g. ISO8859-1/2/15) will fail at runtime.

Compiling in Cygwin environment

Download and install Cygwin environment for Windows with the following extra packages:

make
automake
autoconf
libtool
gcc-g++ development package
ncurses, readline (for user interface)
iconv (character conversion)

Then compile the same way as on Linux. Cygwin builds depend on Cygwin1.dll.

Debugging

It is recommended to install a debug build of the standard library:

libstdc++6-6-dbg

For debugging we need to create a debug build and then we need to start gdb.

./configure CXXFLAGS='-g -O0 -Wall -Wextra'
make
./libtool --mode=execute gdb src/tools/hunspell

You can also pass the CXXFLAGS directly to make without calling ./configure, but we don’t recommend this way during long development sessions.

If you like to develop and debug with an IDE, see documentation at https://github.com/hunspell/hunspell/wiki/IDE-Setup

Testing

Testing Hunspell (see tests in tests/ subdirectory):

make check

or with Valgrind debugger:

make check
VALGRIND=[Valgrind_tool] make check

For example:

make check
VALGRIND=memcheck make check

Documentation

features and dictionary format:

man 5 hunspell
man hunspell
hunspell -h

http://hunspell.github.io/

Usage

After compiling and installing (see INSTALL) you can run the Hunspell spell checker (compiled with user interface) with a Hunspell or Myspell dictionary:

hunspell -d en_US text.txt

or without interface:

hunspell
hunspell -d en_GB -l <text.txt

Dictionaries consist of an affix (.aff) and dictionary (.dic) file, for example, download American English dictionary files of LibreOffice (older version, but with stemming and morphological generation) with

wget -O en_US.aff  https://cgit.freedesktop.org/libreoffice/dictionaries/plain/en/en_US.aff?id=a4473e06b56bfe35187e302754f6baaa8d75e54f
wget -O en_US.dic https://cgit.freedesktop.org/libreoffice/dictionaries/plain/en/en_US.dic?id=a4473e06b56bfe35187e302754f6baaa8d75e54f

and with command line input and output, it’s possible to check its work quickly, for example with the input words “example”, “examples”, “teached” and “verybaaaaaaaaaaaaaaaaaaaaaad”:

$ hunspell -d en_US
Hunspell 1.7.0
example
*

examples
+ example

teached
& teached 9 0: taught, teased, reached, teaches, teacher, leached, beached

verybaaaaaaaaaaaaaaaaaaaaaad
# verybaaaaaaaaaaaaaaaaaaaaaad 0

Where in the output, * and + mean correct (accepted) words (* = dictionary stem, + = affixed forms of the following dictionary stem), and & and # mean bad (rejected) words (& = with suggestions, # = without suggestions) (see man hunspell).

Example for stemming:

$ hunspell -d en_US -s
mice
mice mouse

Example for morphological analysis (very limited with this English dictionary):

$ hunspell -d en_US -m
mice
mice  st:mouse ts:Ns

cats
cats  st:cat ts:0 is:Ns
cats  st:cat ts:0 is:Vs

Other executables

The src/tools directory contains the following executables after compiling.

The main executable:
- hunspell: main program for spell checking and others (see manual)
Example tools:
- analyze: example of spell checking, stemming and morphological analysis
- chmorph: example of automatic morphological generation and conversion
- example: example of spell checking and suggestion
Tools for dictionary development:
- affixcompress: dictionary generation from large (millions of words) vocabularies
- makealias: alias compression (Hunspell only, not back compatible with MySpell)
- wordforms: word generation (Hunspell version of unmunch)
- hunzip: decompressor of hzip format
- hzip: compressor of hzip format
- munch (DEPRECATED, use affixcompress): dictionary generation from vocabularies (it needs an affix file, too).
- unmunch (DEPRECATED, use wordforms): list all recognized words of a MySpell dictionary

Example for morphological generation:

$ ~/hunspell/src/tools/analyze en_US.aff en_US.dic /dev/stdin
cat mice
generate(cat, mice) = cats
mouse cats
generate(mouse, cats) = mice
generate(mouse, cats) = mouses

Note: morphological generation, stemming and analysis only work with dictionaries whose entries carry morphological description fields (po:, st:, is:, ts:, al:, ds:, dp: etc.; see man hunspell.5). The example above relies on the older en_US dictionary linked earlier in this README, which still ships these fields. Most current distributions of en_US, fr, nl and hu_HU do not, and analyze, stem and generate will return empty results for them. This is a dictionary property, not a library bug. See tests/morph.aff and tests/morph.dic for a minimal example.

Using Hunspell library with GCC

Including in your program:

#include <hunspell.hxx>

Linking with Hunspell static library:

g++ -lhunspell-1.7 example.cxx
# or better, use pkg-config
g++ $(pkg-config --cflags --libs hunspell) example.cxx

Installing Hunspell (vcpkg)

Alternatively, you can build and install hunspell using vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install hunspell

The hunspell port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.

Dictionaries

Hunspell (MySpell) dictionaries:

Aspell dictionaries (conversion: man 5 hunspell):

ftp://ftp.gnu.org/gnu/aspell/dict

László Németh, nemeth at numbertext org