16. A word building system as recited in claim 14 , wherein the word building service is further configured to: identify a set of bigrams from the one or more bigrams in the data store, each bigram of the set having the associated count information and including the first letter set as the trailing data word, the set including the first bigram; determine a delta value for the first bigram; and responsive to determining a positive delta value indicating a relationship between the first bigram and the word, compute updated associated count information for the first bigram.
16. A word building system as recited in claim 14 , wherein the word building service is further configured to: identify a set of bigrams from the one or more bigrams in the data store, each bigram of the set having the associated count information and including the first letter set as the trailing data word, the set including the first bigram; determine a delta value for the first bigram; and responsive to determining a positive delta value indicating a relationship between the first bigram and the word, compute updated associated count information for the first bigram. 17. A word building system as recited in claim 16 , wherein the word building service is further configured to associate a new bigram count with the new bigram, the new bigram count computed using the delta value.