The language fictional characters use is chosen for effect, at least if the author is concentrating.
John M. FordAnd bitter waxed the fray; Brother with brother spake no word When they met in the way.
Jean IngelowPeople who keep dogs are cowards who haven't got the guts to bite people themselves.
August StrindbergIf you are a dog and your owner suggests that you wear a sweater suggest that he wear a tail.
Fran Lebowitz