I know the Japanese have individual words for elder/younger brother/sister (兄　弟　姉　妹) but if I wanted to say "he has a brother/sister [whose age I do not know]" how would I say it? Is there a default?

yea

兄弟がいる

Ah, simple as that. Thanks a bunch

On a slightly related note, how do Japanese siblings refer to their parents when speaking with one another? Let's say, for example, I want to tell my sister: "Mom looks nice today". Would I say "my mother" 【母】? Or would I use the general "mother"　【お母さん】? Or would I say "our mother"　【私たちのお母さん】? ((I hope I got all those right)). Is there an affectionate or intimate "Mom" word (as opposed to the somewhat more formal "Mother")? In other words, is there a word that substitutes for her name as opposed to indicating her position in the family?

If I need to get Mom's attention, how would I call out to her? And what about Dad?

Good question. I've heard "ママ", mama being used by little kids in films. I suppose there's one for father, too

母さん - かあさん - is the most common way I see Japanese refer to their own mother within the family

Same with dad, just take the お off.

And you wouldn't need to say "our" in a conversation like this. Everyone already knows who you are talking about from context. Only use personal pronouns when it isn't clear who you are talking about.

Thank you! I never really noticed what people were calling their parents in movies. I'm sure I'll hear it now.

For the record, I often explore a bit more when I learn new vocabulary words. While doing "explore more" on Dad (父さん -- とうさん), I must say I giggled a bit when I found out that is also the pronunciation for "corporate bankruptcy". Hehe .

To make it more confusing:

嬢さん とうさん (n,hon) daughter (of a good family)

saying お母さん when referring to your own mother is very common. Most people will also call their mom お母さん. (With the お is more common than without, I think.) You would certainly never say 母 when calling your own mother.

ママ and パパ are common for little kids as is 母ちゃん and 父ちゃん.

Rekkusu Wrote:To make it more confusing:

嬢さん とうさん (n,hon) daughter (of a good family)

I have never seen that word in my life. I would read that as じょうさん normally.