abc spelling grammar

Hi,

I'd like to know if someone knows a good grammar to spell a name, i tried the simplest :

<one-of>
    <item>a</item>
     <item>b</item>
     <item>c</item>
     <item>d</item>
               ...
     <item>z</item>
</one-of> 

, but it really gives bad results, for example, when i say "b u c" i have "v u c" or "p u c"...I'd like to know if something better exists for grammar to spell words.

Thanks a lot, 

    Yahn Teisseire