It often happens that getting a phrase wrong comes about because people have half-thought about something, but not pursued the issue to its real conclusion. Such an example is the now-epidemic “off my own back”.
It means doing something yourself, using your initiative and not involving others. The fact that it used to be “off my own bat” is neither here nor there (almost). Back works just as well and in fact probably looks the more likely of two options which both seem rather odd.
One theory is that the phrase comes from cricket, a game in which a bat is used to strike the ball, although it is possible for runs (points) to be scored without the leather touching the willow. It’s an unsatisfactory explanation, largely because if it really originated there, it wouldn’t need the “own”. You can’t score runs off someone else’s bat. Even if you’ve borrowed one, it is essentially yours because it is the one you’re using.
On the other hand, “off your own back” implies the effort of carrying something, and “own” fits slightly better there, but again, it’s not a clear, unarguable solution.
It’s an expression that has established itself somehow and , even though no explanation is totally convincing, we know what it means, and only a pedant would take the time/waste the effort required to analyse it.
A much clearer case of incorrect use is “most amount”. John is in the lead because he has the most amount of points. No he doesn’t. He has the greatest amount of points, or perhaps the largest amount. You can hear the cogs creaking in people’s brains as they scan the list of superlatives: largest, biggest, heaviest, blah blah blah, can’t decide. So the generic one, “most”, it is.
When you scrutinise it, though, if you’re going to use “most”, why use “amount” at all? John has the most points. Cricket has the most strange expressions of all sports (it has).
Curiously, this appears to be a modern mistake. It wasn’t common until quite recently, so why has it crept in? Could it be that modern scourge, the ease with which we can communicate publicly? The fact that someone only has to say it once on TV or online and it infects the entire English-speaking world? Incidentally, to describe this phenomenon we use the term “going viral” with no regard for the fact that viruses are overwhelmingly considered to be bad. Nobody celebrates catching a virus, so why should videos, jokes, verbal expressions etc. be said to go viral in a good way?
Now that the English football season is underway (after the briefest of intervals), there is an amusing mistake to be enjoyed occasionally when someone describes a player with a particularly skillful way of kicking the ball. A commentator who knew what he was doing once referred to a player’s “cultured left foot”, and people wishing to repeat it, but who had forgotten the exact word, fished around in the area of their vocabulary that contains “cultured”. What they found in that section was a group of words on the theme of learning, and so came the “educated left foot”.
It tends to be the left foot, perhaps because most of us are right-footed, so it is more remarkable to see a left leg performing sporting works of art.
So there you are: a little tapas plate of expressions that are making their way in the world of the English language. Odd, slightly misshapen, maybe mutant, but hoping to slope along with a hood up and eventually be accepted by the authorities.