We introduce a new publicly available tool that implements efficient indexing and retrieval of large N-gram datasets, such as the Web1T 5-gram corpus. Our tool indexes the entire Web1T dataset with an index size of only 100 MB and performs a retrieval of any N-gram with a single disk access. With an increased index size of 420 MB and duplicate data, it also allows users to issue wild card queries provided that the wild cards in the query are contiguous. Furthermore, we also implement some of

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... smoothing algorithms that are designed specifically for large datasets and are shown to yield better language models than the traditional ones on the Web1T 5gram corpus (Yuret, 2008) . We demonstrate the effectiveness of our tool and the smoothing algorithms on the English Lexical Substitution task by a simple implementation that gives considerable improvement over a basic language model.