A mongrel language

I grew up with mongrel dogs. Their loyalty to their family showed up the moment strangers might wonder near our front gate in a show of canine defence (I use the UK spelling variation). While I know that English is a lovely mix of old and new, local and foreign - courtesy of the Romans, Angles, Saxons, Vikings and Normans (French to you and me) - I wouldn't have thought of applying the word mongrel. So in defence of the mongrel's spelling, and given that this is the Chinese New Year of the Dog, I have added this quote from Michael Harris' What's Wrong With English in the Pearson Longman series, New Opportunities Teachers' Resources:

"It shows where words come from and in a mongrel language like English that must be a good thing. Dessert, cuisine, buffet and restaurant are so obviously French. The silent letters of debt, doubt and receipt all go back to Latin origins and the silent letters of know, knee, folk and alms go back to Middle English."

And for those of you who were paying attention, did you find the 'deliberate' mistake? (smile)