When Hagrid introduces the class to the blast-ended Skrewts, he makes a distinction between the males and females. The former have stings, and the latter have suckers on their bellies. This comparison is symbolic of the adolescent need to make more of a distinction between the sexes. Ron also notices in this book, for the first time, that Hermione is in fact a girl, and Harry finds himself daydreaming not about fame or glory, but about Cho Chang.
Different characters' speech patterns reveal their levels of education. Wizards speak in proper English, and Hagrid, who is half-giant and not fully educated, drops his H's and slurs his words together a bit sloppily. House-elves have no sophisticated mastery of language. They use terrible grammar, referring to themselves in third person and using almost exclusively short, exclamatory sentences. They speak in a manner inferior to that of wizards, and they cannot express themselves clearly or persuasively.