Historically, of course, English did have a so-called tu-vous distinction (T–V distinction) like other European languages. Old English had no politeness distinction, using only þu 'thou' and ge 'ye' as singular and plural respectively. read more
Here is a short blog post of why English is the exception to the general rule! the article Problems with Pronouns is from an English language school in London and talks about briefly about the history of the English language, modern plural forms. read more