For a long time now each generation which has reached middle age has lamented the decline in intellectual ability and civility of the one coming after. Yet civilisation hasn't collapsed. In many ways it is now a better time to grow up than at any time in the past. But the changes over the last half century aren't a mere linear evolution in manners - there seems to be a substantial rupture with the past.
The way in which post-60s generations have kicked off respect for authority has in many ways been liberating. But the reaction or rejection has gone too far and has been far to unselective. This, in my opinion, is one reason why teaching in school is now a barely tolerable task. And it may also explain the explosion in petty, mindless crime. It certainly explains the evaporation of civility from most public spaces.
It seems that we have been gripped by an agressive (and agressively hedonistic) cult of the individual. All of this was underway before the late, great, acceleration of technology into the realm of the personal (where the bywords of marketeers have been 'personalisation', 'customisation', 'unique user experience' - all short hand for individualsim). The twin phenomena of rejection of authority and tradition, and the rapid rise of email, text and other casual forms of communication have cut away the formality - and the discipline - that was once associated with the written word.
Indeed, to mention just one consequence, isn't the demise of letter writing one of the more lamentable side effects of our great leap forward into the age of electronic communication. What a joy for ordinary citizens to have records from their ancestors. But more important, for posterity, what a jewel to have such things as say, the letters of Abraham Lincoln, or those of other eminent persons in the history of any nation.
I cannot claim any great knowledge of the link between proficiency with language and intellectual ability. I would hazard that informality and (what we call) debasement probably have no bearing whatever on the agility of a mind. Even the most slovenly language will be capable of conveying all that is required to run a laboratory - or a country. The great fear would be if the collapse of language were to make its way into literature. There are few greater pleasures than reading a paragraph of prose which shines in impossible beauty. When we reach a stage where literary language has been thus devalued, we should know that we have indeed reached the end of civilisation.