Hi manio,

>how do I know which i shoud use and how to use this phonemes.

I assume you are trying to create an acoustic model for a non-English language. 

What you need is a pronunciation dictionary (as described in Step 2) for your language.  First you need to create a Phoneme list for your language.  The VoxForge phone list looks like this:

    Phoneme Example Translation
        ------- ------- -----------
        AA      odd     AA D
        AE      at      AE T
        AH      hut     HH AH T
        AO      ought   AO T
        AW      cow     K AW
        AY      hide    HH AY D
        B       be      B IY
        CH      cheese  CH IY Z
        D       dee     D IY
        DH      thee    DH IY
        EH      Ed      EH D
        ER      hurt    HH ER T
        EY      ate     EY T
        F       fee     F IY
        G       green   G R IY N
        HH      he      HH IY
        IH      it      IH T
        IY      eat     IY T
        JH      gee     JH IY
        K       key     K IY
        L       lee     L IY
        M       me      M IY
        N       knee    N IY
        NG      ping    P IH NG
        OW      oat     OW T
        OY      toy     T OY
        P       pee     P IY
        R       read    R IY D
        S       sea     S IY
        SH      she     SH IY
        T       tea     T IY
        TH      theta   TH EY T AH
        UH      hood    HH UH D
        UW      two     T UW
        V       vee     V IY
        W       we      W IY
        Y       yield   Y IY L D
        Z       zee     Z IY
        ZH      seizure S IY ZH ER

The IPA web site can help in this regard, or maybe another speech recognition or text-to speech project in your language.

Next, create a Pronunciation Dictionary.  For each word in your training set (i.e. the sentences you recorded) you need its pronunciation using phonemes.  Here is a portion of the VoxForge pronunciation dictionary:

AARP            [AARP]          ey ey aa r p iy
ABA             [ABA]           ey b iy ey
ABACK           [ABACK]         ax b ae k
ABACUS          [ABACUS]        ae b ax k ax s
ABALON          [ABALON]        ae b ax l aa n
ABALONE         [ABALONE]       ae b ax l ow n iy
ABANDON         [ABANDON]       ax b ae n d ih n
ABANDONED       [ABANDONED]     ax b ae n d ih n d
ABANDONING      [ABANDONING]    ax b ae n d ih n ih ng
ABBREVIATED     [ABBREVIATED]   ax b r iy v iy ey t ih d
ABBREVIATION    [ABBREVIATION]  ax b r iy v iy ey sh ih n
ABBY            [ABBY]          ae b iy
ABC             [ABC]           ey b iy s iy
ABC'S           [ABC'S]         ey b iy s iy z
ABCS            [ABCS]          iy b iy s iy z
ABDOMINALS      [ABDOMINALS]    ae b d aa m ih n ax l z
ABDUCTING       [ABDUCTING]     ae b d ah k t ih ng
ABDUCTION       [ABDUCTION]     ae b d ah k sh ih n 

Note that the words are in upper case, the return word is also in upper case and in brackets, and the phones are in lower case.  You need to do the same in your language, for each word in your training set.

You should then be able to create a monophone acoustic model using recordings of your voice using steps 1 to 8 of the VoxForge tutorial.

Ken

Ken,

Thanks a lot for your reply! I got a lot of information here!

sorry for forgetting to tell you I am using Chinese.And what u say are really helpful for me.

and I also got another pdf named

Using English Phoneme Models for Chinese Speech Recognitio

 the url is :www.ece.ust.hk/~pascale/Publications/conference/1998/ISCSLP1998.pdf

maybe it's helpful for others who encounted this problem.

thanx again for what you did in open source development. 

It's nice day tody!

using the method I mentioned below and the with th tutorial in this site, I got a excellent performace in Chinese Small Vocabulary CSR.

 thanks again!