Store "variables" without declaring a variable

I am trying to create a speaking AI. To do this, I am creating a list of classes for every word (or phrase) in the English language. Kind of like Wiktionary has.

Something like this:

class english {
    class lemma {
        class adjective {
            class uncomparable { 
                // Word strings here.
        };
    };  
};

I was wandering if there is any way to store word strings without declaring millions of different variables for speed and less memory. Any ideas?