I'd say

“I’d say” is a conversational filler used to introduce an opinion or estimate, often softening the assertion to sound less definitive or confrontational.

It can signal uncertainty or politeness, as in I’d say it’s about 10 miles from here.

In speech, it often precedes hedging phrases like “probably” or “maybe.” Historically, such phrases have been used to temper statements in English since at least the 16th century, reflecting cultural norms around indirectness and modesty.