Why Does English Add an 's' to Third Person Singular Verbs?

Why does English add an 's' to verbs in the third person singular, such as 'he runs', 'she finds', or 'it changes'? This distinctive feature of English grammar can be traced back to its historical roots. Originally, Old English had a complex system where verbs changed forms according to person, number, and tense, much like Latin and other ancient languages. For example, in Old English, the verb 'to be' had different forms like 'am', 'art', and 'is', depending on the subject. Over time, as English evolved through the Middle English period, influenced by Norman French and Latin, most of these complex verb endings began to simplify. By the late Middle English period, the inflection '-s' started to become standardized for the third person singular form in the present tense. This usage simplified verb conjugation rules and helped clarify subject-verb agreement. Today, this 's' is a straightforward indicator that the subject of the verb is he, she, or it. For example, we say 'I run' and 'you run,' but we need to add an 's' for he, she, or it as in 'he runs,' 'she runs,' or 'it runs.' This small but crucial adjustment helps maintain clarity and grammatical consistency in modern English.