Wilde uses inflated language when discussing trivial thing for humor. What is an example of this?
Most of this inflated language is embodied by Lady Bracknell, especially on Act I when she is conducting her interview on Jack Worthing to determine whether he is suitable enough for Gwendolen.
Some of Lady Bracknell's phrases are key to see the irony of what is said and what is meant. For example, when she asks Jack whether he knows everything or he knows nothing, he responds that he does not know anything. To which she retorts:
I am pleased to hear it. I do not approve of anything that tampers with natural ignorance. Ignorance is like a delicate exotic fruit; touch it and the bloom is gone. The whole theory of modern education is radically unsound. Fortunately in England, at any rate, education produces no effect whatsoever. If it did, it would prove a serious danger to the upper classes, and probably lead to acts of violence in Grosvenor Square.
So, basically, Wilde is insulting the English and the upperclasses by using inflated and ironic language, meaning basically that they are all dumb. Neat, isn't it?
Another great example of inflated language over trivial matters is in Act 3 when Jack and Algernon are arguing over who is eating the muffins and the manner in which they are being eaten. To read the exchange you would think was a very serious situation, but it only muffins! Jack exclaims, "I say it is perfectly heartless your eating muffins at all, under the circumstances." And later he says there is "no reason why you should eat them all in that greedy way." It sounds like two children agruing over a treat rather than two adults -- and these two adults actually have more acute subjects to argue about -- namely Gwendolyn and her supposed engagement to Algernon.