It just seems that 太太、老婆、妻子 are all either overly formal or make my wife sound older than she is (she's not even 30). Maybe one of those terms is actually more acceptable than I think it is; I don't know. Are there any other options that would be more socially appropriate?
When you introduce your wife both 太太 and 老婆 are acceptable, depending on whether it's a formal occasion. 太太 is more formal while 老婆 is more casual. Both are socially appropriate.
Although dictionary says it's used in past (旧时) , people are actually using this word more and more often in recent decades. If you are going to introduce your wife to new friends, business partners, or acquaintances, 太太 is the word you should use.
In comparison, other pronouns to introduce one's wife include:
- 老婆: used in casual and informal occasion, like with close friends or relatives. Especially, you can use this word to directly address your wife.
- 妻子: extremely formal. most likely only used in written language, e.g marriage certificate, court decision, etc.
- 夫人: rarely used to introduce one's own wife. Generally, 夫人 is used to introduce someone else's wife, to show respect (to the husband), cause the word 夫人 hints that the husband is socially recognized and esteemed.
- 内人: archaic.
- 爱人: used to be the right word to introduce one's wife. But it was like 30 years back... Now it's also old and rarely used (only by senior people)
- 媳妇: acceptable in casual occasion, but only used in northern China.
In present day Beijing, the term 对象 (dui4 xiang4) is often used to introduce one's spouse. I would translate 对象 as "counterpart".
Literally, 对象 means "object". "Object" refers to that which is perceived by a subject. For example, as English grammar dictates, when you love your wife, you are the object and your wife is the subject of your love. Although I need to clarify that the grammatic concepts of "subject" and "object" are technically translated as 主语 and 谓语 respectively.
A few months ago, I visited Dalian in the Liaoning province of China. The people there drew a distinction between 对象 and 爱人, with the former term as referring to a partner before marriage and the latter term referring to a spouse. This constrasts with my experience in Beijing, where people referred to their spouses as 对象. I guess that this distinction started to be drawn more recently as historically a Chinese would introduce one's partner as such only after their marriage has been planned.
I have heard this used in modern TV shows -- usually face-to-face (husband to wife) -- as 情爱的 。。。I suppose it works just as well when you are introducing someone by saying 。。。这是我的情爱的。。。literally: This is my loved one.
This might work better in certain circumstances when you are uncomfortable saying 太太，老婆，or 爱人, which I will agree seems a bit formal or has misinterpreted meanings...
The wikipedia has a list of all the words that refers to someone's wife: