Formal:
* 爸爸 (bà ba): This is the most common and neutral way to say "father" in Chinese. It's suitable for most situations, even when addressing your own father.
Informal:
* 爹 (diē): This is a more informal and affectionate way to say "dad" or "father." It's often used by children or close family members.
* 爸 (bà): This is a shortened version of 爸爸 (bà ba) and is also considered informal.
* 老爸 (lǎo bà): This literally means "old dad" and is a very affectionate term used by children or close family members.
Other options:
* 爸爸 (bà ba) can also be used as a term of endearment for a romantic partner, similar to "daddy" in English.
Which one to use:
* For your own father: Use 爸爸 (bà ba) or 爹 (diē) depending on the context.
* For someone else's father: Use 爸爸 (bà ba) unless you are very close to them and know that they use a more informal term.
It's important to note that the use of these terms can vary depending on region and dialect.