Found myself commenting in class this morning on a particularly Singaporean use of the word elderly. The term is used frequently as a noun here, as in, I was talking to an elderly, or, The elderlies suffer from short term memory loss. I'd say the usage of the word in this sense qualifies as educated Singaporean English - as opposed to being an uneducated error. I've noticed that even when 'corrected' or informed of the Standard English usage most students are resistant to bothering to take care over its use.
It's interesting to speculate as to how the local usage came about. I can see three contributory factors. The 'correct' use as an uncountable noun - as in, In a civilised society the elderly are treated with respect and cared for - is likely to have influenced the adoption of the word as a countable noun, and I'd guess would have been the most important factor involved. Then there's the slight clumsiness of needing to say, The elderly people were crossing the road. Substituting elderlies seems so much pithier. And finally I think there's a good chance that the perfectly acceptable countable noun elder is involved in all this - perhaps as a kind of mishearing, or possibly because it feels a bit prissy to say, The elders were crossing the road.
All this reminded me of the current POTUS's noticeable habit of using modifiers as nouns. The other day we got, If we had bi-partisan in his puzzling reflections on the failure of Trumpcare (or Ryancare, not sure which) to make it into law. I presume he was expressing a desire for bi-partisan support, though it's difficult to tell where this president's thoughts are leading him, if anywhere.
Oh, and I should confess that I might have forgotten the linguistic excitement of the morning were it not for the fact that a colleague described me, with grammatical accuracy and, sadly, a bitter regard for the truth, as a lean and elderly figure, later in the day. Ouch.