The smallest sentence in the English language is "I am." From that small, but important sentence words can be added to build a bigger language construction. "I am very hungry for chocolate."

In Spanish, the smallest sentence is "Yo soy." That also means, "I am." Both verbs, "to be," and "yo soy," are irregular, meaning that  they do not fit a particular pattern. Many verbs do fit pattern, and so verbs are either regular, or irregular. What is interesting is that the most common verbs in both English and Spanish,  have irregular patterns, and they are the most important verbs, too.