title: How to concatenate phone hmm model to a composite word or sentence hmm model
body: <p>I want to do the embedded training for speech recognition. In the beginning, I want to use the monophone with 3-states, as the paper decripted, I can concatenate all the phones in one word or sentence to make a composited hmm model, and do embedded training on the composited hmm model. </p>
  
  <p><em>like this picture:</em></p>
  
  <p><a href="https://i.stack.imgur.com/VNTiI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VNTiI.png" alt="concatenate phone hmm models"></a></p>
  
  <p>I am puzzled when I try to do this, there are some problems puzzled me.</p>
  
  <ol>
  <li><p>3-states phone model also have other 2 states, begin state and end state, generally the transition only allowed happend on self state to self state and self to next state. <strong>So what is the transition should be from one phone end state to next phone start state? Or the start and end state should be ignored when concatenating?</strong> I found HTK cookbook direct to concatenate the start and end state, but set transition from one phone end state to next phone start state to 1.0.</p></li>
  <li><p>One word may contains a phone in many times, how to concatenate the same phone in A(transition) matrix and B(emission) matrix? I understand to concatenate the A matrix directly with the transition from one phone end state to next phone start state 1.0. The B matrix was shared, the same phone state has the same emission distribution.</p></li>
  <li><p>I have may different words to train. After I trained one word, I got the three parameters: A matrix, B matrix, and Pi for the phones in the word, how can I use these parameters to train another word? </p></li>
  </ol>