HTK Speech Recognition Toolkit
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Installing HTK on Microsoft Windows


  • HTK has been verified to compile using Microsoft Visual Studio.
  • For testing, you will require a Perl interpreter such as ActivePerl.
  • You will need a tool such as 7-zip for unpacking the HTK source code archive.
  • Register on this site by accepting the HTK End User Licence Agreement, then download the latest HTK source code.
  • It is helpful if you have some familiarity with using the DOS command line interface, as you will need to interact with it in order to compile, install and run HTK.
  • Ensure that your PATH contains C:\Program Files\Microsoft Visual Studio\VC98\bin


  1. Unpack the HTK sources using 7-zip.
  2. Open a DOS command window: Click Start, select Run type cmd at the prompt and click OK.
  3. cd into the directory in which you unpacked the sources.
  4. cd into the htk directory. Type:
    cd htk
  5. Create a directory for the library and tools. Type:
    mkdir bin.win32
  6. Run VCVARS32 (it should be in your path, see prerequisites above)
  7. Build the HTK Library, which provides the common functionality used by the HTK Tools. Enter the following commands:
    cd HTKLib
    nmake /f htk_htklib_nt.mkf all
    cd ..
  8. Build the HTK Tools
    cd HTKTools
    nmake /f htk_htktools_nt.mkf all
    cd ..
    cd HLMLib
    nmake /f htk_hlmlib_nt.mkf all
    cd ..
    cd HLMTools
    nmake /f htk_hlmtools_nt.mkf all
    cd ..


The HTK tools have now been built and are in the bin.win32 directory. You should add this directory to your PATH, so that you can run them easily from the command line in future.


Among the samples on the HTK website you'll find the HTKDemo package that can be used to test your installation.

As an initial test of the installation please run the HTK demonstration using the configuration file HTKDemo/configs/monPlainM1S1.dcf. There is a README file in the HTKDemo directory explaining the operation of the demonstration in detail but, in short, you need to run the demonstration script passing it the configuration file configs/monPlainM1S1.dcf as input. To test the language modelling tools you should follow the tutorial in the HTK book, using the files in the LMTutorial/ directory.

Before running the demo make sure you have compiled all the HTK tools and the executables are in your PATH, i.e. just typing 'HInit' at the commandline prints a short usage summary. To run the demonstration type:

cd HTKDemo
perl configs/monPlainM1S1.dcf

The recognition results obtained should match the following.

On the training set:

------------------------ Overall Results --------------------------
SENT: %Correct=0.00 [H=0, S=7, N=7]
WORD: %Corr=77.63, Acc=74.89 [H=170, D=37, S=12, I=6, N=219]

On the test set:

------------------------ Overall Results --------------------------
SENT: %Correct=0.00 [H=0, S=3, N=3]
WORD: %Corr=63.91, Acc=59.40 [H=85, D=35, S=13, I=6, N=133]

Comments and suggestions to