> Hey! How come "nonsensical" is a word, but "sensical" isn't? How is it possible to negate something that doesn't exist?

Because 'nonsensical' is not a negated form of the ficticious 'sensical.' It is the adjective form of the noun 'nonsense,' which is the negated form of 'sense,' which has its own adjective form: sensible.

Which brings about another question. Why do we constantly hear words like the nonsensical 'conversate' in the place of perfectly acceptable words like 'converse'? (Note the use of the British punctuation!) Has our society just gotten too lazy to recall the proper verb forms of common nouns? I have had the misfortune(or should I say 'unfortune'?)to hear professional broadcasters use this word! Does this happen in other cultures besides that which uses American English?