As far as I know, neural networks have hidden computational units and HMM has hidden states.
Hidden Markov Models can be used to generate a language, that is, list elements from a family of strings. For example, if you have an HMM that models a set of sequences, you would be able to generate members of this family, by listing sequences that would befall into the group of sequences we are modeling.
In this, this and this paper, HMMs are combined with ANNs. But how exactly? What is a Hidden Markov Model - Artificial Neural Network (HMM-ANN)? Is HMM-ANN a hybrid algorithm? In simple words, how is this model or algorithm used?