Now I’m not American … or English … but I am a native English speaking Australian.
In the extremely English sport of cricket, all sorts of terms are used to describe the ball doing something mysterious, usually by the intention of the bowler or the mistake of the batter.
For example, when the cricket ball gets old, it can be swung in the opposite direction to the way it swings when it’s new, with no visible change in the bowler’s action. This is called Irish Swing.
Also for example, slow bowlers generally impart a spin on the ball to make it go one way or the other after bouncing, thus confusing the batter. One of the stock deliveries of slow bowlers is one that looks as though it is going to break one way and then breaks the other. This is called a Chinaman.
And further for example, there is a rather elegant batting stroke called the cut. A misplayed cut, where the ball comes off the bat obliquely in an unintended direction, is called a French cut.
All this is by way of suggesting that perhaps the use of “English” could originate in the same type of somewhat perjorative word use, where something opposite is called Irish, something inscrutable and untrustworthy is Chinese, some mistake is called French. Taking it further, an Indian giver, going Dutch; so something English is … weird, unexpected, clever, sophisticated, untrustworthy, tricky, duplicitous?
my $0.02
Link to staff report: What’s the origin of "English," the kind you put on a ball? - The Straight Dope