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 Disk/disc 

Angr, this is a very interesting essay (but being a stuffed up Brit I cannot agree with it!). However, I think I need to point out that 'disc' is not a verb in British English. 'To disk' (Amer. Spelling) may be a verb in US Eng. (meaning something to do with ploughing), and this will be why the inflected forms appear as 'disking' and 'disked'. The forms *discking and *discked could not exist simply because 'disc' when spelt with a '-c' is British English and is not a verb.  (A word...?) "