Someone who lives on the same floor as I do has discovered that the down-arrow button at the elevators can be rotated to point sideways or upwards. Practically every day now, I come to the elevators and find it pointing the wrong way. Just out of a habit of tidiness, I turn it to point down. But lately it doesn’t take long for it to be re-pointed. I have no idea who’s doing it; I’m not aware of any adolescent boys living on my floor of the building. Well, whoever is doing it is certainly a bit childish.
Does it do harm? No, but it’s disruptive for the sake of being disruptive. It aims to call attention to itself. Now, children love to play, and they are known for having open and inquisitive minds (although mothers of some picky eaters may snort at the idea); that’s not a bad thing at all. Simple joy and wonder is very engaging and something we ought not to lose; it is even recorded that Jesus enjoined his followers to be like children. But was he asking them to be childish? Or childlike?
So what’s the difference? Both childish and childlike signify behaviour that recalls the behaviour of children. Why wouldn’t they mean the same thing? Why even have two words for it?
Well, we know why. Children are little angels and little devils all rolled into one – a child may be mild or wild, and we may stop and wonder whether it’s only coincidence that those three words (child, mild, wild) have come to be the three rhymes with that spelling. And adults who emulate some quality of a child may emulate a positive or a negative one. So the word we use varies accordingly. It’s a difference of tone, of connotation. There are even contexts in which one could safely use childlike but would risk tut-tuts or worse for using childish – it’s such a deprecatory term as to be itself a touch improper, because insulting.
It’s a sign of maturing linguistic understanding when a person comes to realize that denotation is not all there is to words. Words are known by the company they keep, for one – certain words for certain things are unacceptable in contexts where other words for the same things are perfectly allowable. And this is, of course, also related to the connotations and implications of words – which are bound together with the pragmatics of their usage. If I use a vulgarity where I might have used a polite Latinate word that denotes the same thing, it means that I am aware that I am being transgressive, impolite, and maybe a bit childish too. For that matter, if a mother calls to her son, “Stevie,” it simply means she wants him to come see her (though the tone of voice will certainly matter), but if she calls out “Stephen Maxwell Davidson,” the formality probably means she’s upset with him, even though the denoted object is the same and the required action is not per se different.
But, now, why negative ish and positive like? At this point we must wander into speculation. It would seem reasonable that like would be more likeable. It has shown up repeatedly in words such as godlike and gentlemanlike, after all – but also in such as devil-like and Brutus-like. Still, it has that light sound and the lick and kiss of /l/ and /k/. And it has been reinforced by usages in translations of the Bible and by such writers as Shakespeare (“I thought the remnant of mine age Should have been cherish’d by her child-like duty” —Two Gentlemen of Verona).
As for ish, it, too, has had its tone reinforced by Shakespeare (“What cannot be avoided, ‘Twere childish weakness to lament” —Henry VI part 3) and others. And while it may rhyme with wish, it is more wishy-washy in tone: things that are ish are imitations or are inclined towards something, and perhaps not something esteemed. We know foolish, of course; those opposed to Roman Catholics have over history referred to Popish people; even if it appends to something positive, ish may weaken it: “Is she pretty?” “Prettyish.” I can’t think its sloshing, hissing sound helps, either.
But can we find counter-instances? Would we find similar results with other words suffixed with the same pair? Hmmm… we know clownish; how would we receive clownlike? Mannish versus manlike? (Manlike, like gentlemanlike, appears more often in the related form with ly in place of like.) Some would produce semantic differences – bookish is not like booklike. The only one I can think of that would go the other way is one where the ish form has undergone amelioration: devilish shows up with words such as charm, where as devil-like, not commonly used, just means “like a devil”.
And how about other cases (not involving these suffixes) where a parallel denotation results in an opposite connotation? I leave this as an exercise to the reader. It should be easy. Or easyish, anyway.