For the basic word list, possibly tries (https://en.wikipedia.org/wiki/Trie), DAGs (https://en.wikipedia.org/wiki/Directed_acyclic_graph#Data_co...), or Bloom filter (https://en.wikipedia.org/wiki/Bloom_filter)
When you need to store your dictionary in under 1 byte per word, a trie won't cut it.
The error rate goes up to 1 in 66 for 256KB (in memory only);