What is the difference between 你好and 你好啊? Does adding 啊 to the end of 你好 make any difference in its use? Are these two phrases interchangeable or not? Are there any preferences for either of the two in certain situations?
It seems to me that 你好啊 sounds like saying hello in answer to someone else's greeting. But I'm not sure.
Usually, we use "你好" to answer "你好". It could be used in any circumstance. It sounds neutral. It's fine to greet anyone using "你好".
Compared with "你好", ‘你好啊’ is warmer. It is much less used than "你好". For example, if you see a cute child, you can say “你好啊，小朋友”.
By the way, there is an interesting little story about "你好". Wang Xiaobo, a famous Chinese writer, used it as the beginning of the Love letter and it has become one of the most romantic love words in China:
“你好哇，李银河！” —— 出自《爱你就像爱生命》
“你好哇, Li Yinhe！” -- from 《Loving you is like loving life》
"你好哇" has become a very implicit and intimate greeting.
they are just ways of exchange greetings with effects similar to say "howdy" instead of "hello".
