Illiterate, or just "linguistically challenged"?

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• Below is an edited exchange from Facebook recently about the letter above which was written by a prominent Scottish Nationalist who appears not to understand the difference between two ordinary English words: "extraction" and "retraction". 
• It is pretty shocking, really, though not to at least one supporter - see below.

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  You "extract the mickey", but you "retract an allegation". It is staggering just how ill-educated the "cluvvr" folk so often turn out to be. I have no "issue" with ill-educated people, but anyone who gets on their high horse and takes snooty line with others ought to be able to say what they want to say without embarrassing themselves by lapsing into unintentional humour.5 April at 22:35 · Like · 2олег волконский Extraction has the unfortunate association with teeth.
  5 April at 22:40 · Like · 1Ian Mitchell "Ex" is a Latin prefix which can mean to take or go out, as in exit, exfiltrate, or excommunicate. "Re" in this context can mean take or go back, as in return, resume, or retrieve.
  5 April at 22:51 · Edited · Like · 3
  Brian Macfarlane · One mistake from a man in his seventies makes him "not literate? FFS I got that shit from another asshole on the Torygraph bloody snobs GTF
  18 hrs · Like