How to change input method on 5.1.1 I cannot see the "select input method" command in the pull down menu like in Android 4.
By experimenting, I discovered you can select the input method if you long-press the space bar in Samsung keyboard.
I used this to switch to Hacker's keyboard.
But that keyboard doesn't support the space bar long press convention.
So, I cannot change back.

Edit: the long press method is a feature of Google Japanese Input, not the Samsung Keyboard, sorry. I can change the input method via Settings/Language and input/Default Keyboard. That is far too inconvenient for regular use.

Edit: I remember seeing on some Android version a good mechanism for this: a little keyboard icon displayed while in input mode. I feel it must be somewhere; I'm just not looking in the right place.
Found it. Stupidly, you have to pull down, then scroll through the entire stack of notifications. "Select Keyboard" is buried at the bottom!