Difference between duō dà and jǐ suì

First, "duo da" (多大) literally translates to "how big" and is commonly used to ask someone's age in a direct way, like "你多大？" meaning "How old are you?" It's straightforward but can be considered informal. I should note that in some contexts, especially with elders, it might be too blunt.

Then there's "ji sui" (几岁), which also asks about age but uses "几" (a few) and "岁" (years old). This phrase is more polite and is often used when talking to children or in formal situations. For example, "你几岁？" is "How old are you?" but sounds softer.

Wait, but I need to make sure about the nuances. In some regions, "ji sui" might be more common for kids, while "duo da" is for adults. Also, "duo da" can sometimes be used for objects, like size, but the user is focusing on age.

I should also mention politeness levels. Using "您多大年纪？" (nín duō dà nián jì) with "您" is more respectful for elders. Whereas "ji sui" is okay for children but might be too direct for adults.

Are there any exceptions or other contexts? Maybe in written vs. spoken language? Probably not a major factor here. The key points are formality, target age group, and regional usage.

I need to present this clearly, making sure the user understands when to use each phrase appropriately. Examples would help. Also, highlight that "duo da" is more versatile but can be informal, while "ji sui" is specific to age and more polite for younger people.