It may be natural to think that your own tongue is complex and mysterious. But English is pretty simple: verbs hardly conjugate; nouns pluralise easily (just add “s”, mostly) and there are no genders to remember.The exploratory essay was interesting to me primarily for how much it gets wrong. Not the fascinating anecdotes about languages, which I grant are accurate, but in its poor logic right down to the root.
English-speakers appreciate this when they try to learn other languages. A Spanish verb has six present-tense forms, and six each in the preterite, imperfect, future, conditional, subjunctive and two different past subjunctives, for a total of 48 forms. German has three genders, seemingly so random that Mark Twain wondered why “a young lady has no sex, but a turnip has”. (Mädchen is neuter, whereas Steckrübe is feminine.)
If your native language is one without tones, then languages with tones will be difficult for you to learn. If you grow up speaking a language with 19 cases, it will not seem hard to you, any more than English seems hard to six-year-olds just because it has such things as gerunds and prepositional phrases. Such things are mostly noticeable only from the outside. There is a hoary tale - likely apocryphal - among linguists of an aboriginal from some remote part of empire who studied linguistics in London. When asked by the School of Oriental Languages to prepare a grammar on his native tongue, he declared that it had no grammar.
I should note that I am grateful to the author for taking down the general misconception about gender in languages in as succinct a manner as I have seen. It is related to the word genre, which is a more accurate concept. While it is not entirely accidental that the genders in the languages we are most familiar with - natural gender is related to grammatical gender, it is equally true that we might have named them blue, red, and green noun classes instead of masculine, feminine, and neuter.
In the main, however, all the engaging examples the Economist article describes are completely beside the point. Children master their native language between four and six years old regardless of the difficulty it might present to outsiders. There are a few languages in the Caucasus which take eight years for children to master, and these might thus lay some claim to being most difficult; also, languages which are spread wide in the world and touch on many subjects always have more that one can learn in them. But whether languages are agglutinative or have many cases are mere accidents. It does not make them harder in any real sense. Even the fascination with those most unusual of consonants, the clicks of a few African languages, turns out to be more a mark of simplicity than complexity. The clicks were likely there in the earliest language and have gradually disappeared over millennia. They are an adaptation to the sudden need for more complexity in language before our tongues and voiceboxes had quite fine-tuned themselves as they are now. They are most likely related to more primitive primate calls and sounds pressed into service for new, nuanced thought. But it would be odd indeed to think that languages have gotten simpler over the last 50,000 years because they have lost the clicks.
Our brains used to distinguish among smells far better than they do now; losing that ability does not mean our brains have gotten more stupid.