In our case, we define a bigram model by assuming each word has a different distribution over the words that follow it, but all these distributions are linked.
the definition of our bigram language model as an HDP is P (w i |w i−1 = w) is distributed according to H w , a DP specific to word w. H w is linked to the DPs for all other words by the fact that they share a common base distribution G, which is generated from another DP.