There are various synonyms for the phrase "I say" that can be used to make our speech more interesting and varied. One alternative to this phrase is "I suggest," which indicates that you are proposing an idea without being forceful. Another option is "I advise," which conveys that you are giving guidance or making a recommendation. "I maintain" is a good synonym when emphasizing that you stand firm on a particular point, while "I propose" is helpful when presenting a new idea. Lastly, "I contend" is a good option in a debate or argument, indicating that you strongly believe in a particular point of view. By using diverse synonyms, we can make our speech more engaging and dynamic.