Thank you for yourthe encouragement. Thank you for the encouragement.

Additionally: Thank you for your encouraging remarks. Thank you for encouraging me.

(In fact / To be honest), I don't think my English is that good. (In fact / To be honest), I don't think my English is that good.

This works - just sounds a little unnatural.

In factTruthfully, I don't think my English is that good. Truthfully, I don't think my English is that good.

I can't speak English fluently, and. I can write in English, but I often make grammar mistakes. I can't speak English fluently. I can write in English, but I often make grammar mistakes.

More natural

I can't speak English fluently, and. Though I can write in English, but I often make grammar mistakes. I can't speak English fluently. Though I can write in English, I often make grammar mistakes.

I can't speak English fluently, and although I can write in English, but I often make grammar mistakes. I can't speak English fluently, and although I can write in English, I often make grammar mistakes.

It sounds weird and unnatural to hear something negative (can't) and positive (can) and then "but...". You could also separate it into two separate sentences if you prefer that.

I can't speak English fluently, and; I can write in English, but I often make grammar mistakes. I can't speak English fluently; I can write in English, but I often make grammar mistakes.

I can't speak English fluently, andbut I can write in English, butalthough I often make grammar mistakes. I can't speak English fluently, but I can write in English, although I often make grammar mistakes.

So I still need to improve. I still need to improve.

I can't speak it, I can't understand it, but I listened to many Cantonese songs that weare sung by some very famous Hong Kong singers. I can't speak it, I can't understand it, but I listen to many Cantonese songs that are sung by some very famous Hong Kong singers.

I can't speak it, I can't neither speak nor understand it, but I listened to many Cantonese songs that were sung by some very famous Hong Kong singers. I can neither speak nor understand it, but I listen to many Cantonese songs sung by some very famous Hong Kong singers.

I can't speak it, I can't understand it, but I have listened to many Cantonese songs that were sung by some very famous Hong Kong singers. I can't speak it, I can't understand it, but I have listened to many Cantonese songs that were sung by some very famous Hong Kong singers.

"Listened" makes it sound like you only listened to them once or all in one sitting and I don't think that is what you mean.

I can't speak it, I can't understand it, but I've listened to many Cantonese songs that were sung by some very famous Hong Kong singers. I can't speak it, I can't understand it, but I've listened to many Cantonese songs that were sung by some very famous Hong Kong singers.

your version is not incorrect, but present perfect sounds more natural here

That Beijing uncle will beis my role model. That Beijing uncle is my role model.

ThatMy uncle in Beijing uncle(?) will be my role model. My uncle in Beijing (?) will be my role model.

Not sure what you are trying to say here, exactly.

That Beijing uncle will be my role model for improving my English. That Beijing uncle will be my role model for improving my English.

I suggest combining this sentence and the one afterwards' ideas for clarity.

ThatMy Beijing uncle will be my role model. My Beijing uncle will be my role model.

SoI want to improve my English so that when I travel overseas, communicationg in English-speaking countries won't be a problem. I want to improve my English so that when I travel overseas, communicating in English-speaking countries won't be a problem.

I specified English-speaking countries for clarity.

So wWhen I travel overseas, communication won't be a problem. When I travel overseas, communication won't be a problem.

But I still want to learn English. But I still want to learn English.

You could combine this with previous sentence, but this works too!

ButHowever, I still want to learn English. However, I still want to learn English.

I don't want to waste my spare time,. I want to improve myself. I don't want to waste my spare time. I want to improve myself.

I don't want to waste my spare time, and I want to improve myself. I don't want to waste my spare time, and I want to improve myself.

I don't want to waste my spare time,; I want to improve myself. I don't want to waste my spare time; I want to improve myself.

Although learning a language is so difficult, it brings me a lot of joy and allows me to meet new kind, friendly people. Although learning a language is so difficult, it brings me a lot of joy and allows me to meet new kind, friendly people.

Although learning a language is so difficult, it brings me a lot of joy andjoy and allows me to meet kind, friendly people. Although learning a language is so difficult, it brings me joy and allows me to meet kind, friendly people.

Although learning a language is sovery difficult, it brings me a lot of joy and kind, friendly people. Although learning a language is very difficult, it brings me a lot of joy and kind, friendly people.

A more natural word choice for this sentence is very.

Although learning a language is so difficult, it brings me a lot of joy and the opportunity to meet kind, friendly people. Although learning a language is so difficult, it brings me a lot of joy and the opportunity to meet kind, friendly people.