In general, you form the past tense of an English verb by adding –ed (or just –d if the verb ends in e) and, in some cases, making minor spelling tweaks. Talk becomes talked, love becomes loved, hop becomes hopped and holp becomes helped. As anyone who knows even a bit of English is aware, however, the language also contains many irregular verbs. In fact, according to some counts, fifteen of the twenty most common English verbs are irregular.
Strong and Weak Verbs
Why does English have so many irregular verbs? The answer is complicated, but it all started with Old English. Like other Germanic languages, Old English had some verbs that fell into a category called “strong verbs” and some that fell into another called “weak verbs.” (There were many subclasses within these categories, but no need to worry about them for now.)
The systems for conjugating both sets of verbs were complex, as are the systems’ evolution over time, especially when you take past participles into account. However, to simplify, speakers of Old English conjugated the strong verbs by changing their vowel sounds. Some of the verbs we inherited from Old English still follow this pattern; think of give-gave or sing-sang.
Speakers of Old English conjugated the weak verbs by adding endings. This is where the –ed rule in contemporary English comes from. New verbs come into English through contact with other languages. Like dunk, which entered English from German in the modern era. Then the invention of new words (like email), or the verbing of nouns (like impact), native speakers automatically conjugated using –ed. Therefore, as English vocabulary has grown, the proportion of verbs that take –ed has climbed. This is one major reason adding –ed is now the “regular” way to conjugate English verbs.
From Holp to Helped
Research shows that the words people use most often are the words least likely to change, simply because people use them so much.
Think about it: a fluent English speaker is unlikely to say thinked for the past tense of think or writed for the past tense of write. Especially since they say and hear thought and wrote all the time. However, if you need to say the past tense of plead, would you say pleaded or pled? For bide, would you say bided or bode?
If you’re unsure, the reason is probably that you don’t use the past tense of plead or bode too frequently. The less often people say or hear the past tense of a verb, the less likely they are to remember it.
Sometimes people forget the past-tense forms of irregular verbs that they say or hear only rarely. When they do need to use the past tense of the verb, they may automatically conjugate it as if it were a regular verb (i.e., they add –ed). If enough people do this, eventually, the regularized, -ed form takes over as the standard conjugation. Regular verbs become irregular, too, but this happens less often.)
The past tense of help (went through this process). Originally, help was a strong verb and its past tense was holp, as in “She holp her mother.” However, people slowly forgot about this irregular form and started adding an –ed to help instead. The Oxford English Dictionary reports that the regularized form helped appeared as early as 1300. And by the end of the seventeenth century, helped had pretty much taken over — help had become a weak verb.
Why Are Irregular Verbs Used So Often?
If most English verbs take –ed, then why are so many of the common words irregular?
To borrow a metaphor from Kevin Stroud on the (History of English podcast), English is a little bit like a tree. The branches represent words and linguistic features from Latin, French, and other sources. They are numerous, but they are relatively new and relatively likely to snap off and disappear. The roots and trunk of the tree – the central, lasting parts – are mostly Germanic and based on Old English. Most of the words we use every day, most of the words native English speakers use are inherited from Old English.
Among these commonly-used words are descendants of Old English strong verbs. Because we use them so frequently, they tend not to change over time. So most of them, unlike help, retain their original past tense forms.