How to say this in Japanese?

Hi all,

I was very fortunate to meet and engage conversation with Japanese people during my previous trip. They are very kind to understanding towards my limited Japanese language skill and helps me to practice it out. There are some common topics I have difficulties to craft the sentence. Hopefully I can get some help from this forum on how to say these for my next trip

- "I'm Chinese (by ethnic but not from China)"
- "I learnt (the language) by myself"

- When a passerby trying to talk to me in Japanese, thinking I'm a local, how is the polite way to say that I'm a foreigner and have limited skill in the language

- How to address elders? In my country, we used to use "uncle" or "auntie" to politely address elders, but I'm not sure if people are comfortable being addressed as "ojisan" and "obasan".

- For hotel which requires calling for pick-up service, how should I start my sentence and request for the pickup? Should I start in English to indicate that I'm a foreigner, or in Japanese asking to be picked up?

Your advise will be greatly appreciated. Thank you very much!

- Saying "Chuugoku-kei Shingapooru-jin desu" (I am Singaporean of Chinese descent) would be fine.

- "Dokugaku de manabimashita. (I learned it by myself/on my own.)

- Sumimasen, nihongo wa amari wakarimasen. (Sorry but I don't understand much Japanese.)

- Elders close to you or not? If you know the name, "(family name)-san" would be generally used. I don't know how old (or young) you are, but particularly "obasan" can annoy women of certain age group.

- Does the hotel provide that pick-up information in English? Then I would just speak in English.
You could try:
- Pikku-appu wo onegai shitai no desu ga. (o'clock)-ni (place) made onegaishimasu. (I would like to ask for pick-up. Please come to (place) at (time).)

Awesome, thank you AK.

Regarding addressing elders, I'm referring to strangers, e.g. fellow hiker, locals I met, etc. A kind middle-age hiker walked with me along Kamakura trail and we chatted in Japanese despite of my minimum language skill. But I didn't know how to address him. For example, when he is asking something about me, I want to say "what about you?". I didn't know if I should replace the "you" with "anata" or "ojisan", but I'm worried using "ojisan" will insult/annoy him".

With strangers... I would say "anata wa?" or "sochira wa?" ("Sochira" means "that way," or "that side," and can be referring to the party you are speaking to, in polit e terms.)

Ojisan in that situation can... sound a bit off :)

"Sochira wa" sounds good. I feel more comfortable using it than "Anata wa". Thank you very much, AK!