Modal verbs are a distinct category of verbs in English that function differently from regular verbs in several key ways. While regular verbs primarily express actions or states, modal verbs modify the meaning of other verbs by indicating various nuances such as necessity, possibility, permission, ability, obligation, or probability.

One fundamental difference lies in the fact that modal verbs do not inflect for tense, person, or number, unlike regular verbs. This means modal verbs remain the same regardless of the subject or the time frame of the action. This fixed form contributes to their unique role in sentence structure and their ability to convey specific meanings efficiently and accurately.

Moreover, modal verbs are always followed by the base form of another verb (without ‘to’) and cannot function as the main verb in a sentence on their own. For example, in the sentence “She can sing,” ‘can’ is the modal verb modifying the main verb ‘sing’. This distinctive grammatical structure differentiates modal verbs from regular verbs.

In terms of usage, modal verbs play a crucial role in expressing the speaker’s attitude, opinion, or stance towards a particular action or situation. They add shades of meaning that go beyond simple action descriptions, allowing for nuances in expressing certainty, possibility, obligation, or ability.

Overall, the unique grammatical characteristics and specific functions of modal verbs distinguish them from regular verbs, making them essential tools for expressing a wide range of meanings and adding depth to the English language.