Comment by bozho

It's not that easy today either. Loading a list of words in a hashtable will work for..Chinese (pinyin), but most languages have declensions and conjugation. And you want to validate both "cat" and "cats", both "walk", "walking" and "walked" and the word list normally wouldn't contain those. (haven't checked the English ones, but it certainly doesn't for languages with more complex inflection).

Yes, you don't have the memory complications that are really hard, but you still need to think. Get a proper data-structure (Trie, for ex), and fill it with all forms of the words.