A little bit of a back story; I work in an international company in Hong Kong where the main languages are Cantonese and English. Our team in HK is only 3 people (4 if you include one temporary person from another team), our main team is in Singapore and is about 15 people.
Ever since I joined, there has been a language issues, my 2 local colleagues are both from HK and they tend to speak Cantonese in the office. I've pointed out several times that I feel excluded and that I'm not able to help them with the problems they face at work if they don't communicate in English. I know that they're having a lot of problems, but they mostly communicate with the team in SG over Skype. I feel this is just a waste of time and it would be easier if they spoke to me.
I've had numerous meetings with them about this problem and have continued to ask them to try and use as much English as possible in the office. I've mentioned that I don't mind they speak Cantonese to discuss personal problems (since that's none of my business), but when it comes to anything related to the project, I would like them to use English since it will affect me. (English isn't my native language as well, but it's the only language we have in common)
Now we're over a year later and this problem still continues, I've brought it up to my manager who eventually discussed it with them. Since them things have taken a turn for the worst and now they hardly speak at the office. I've tried to discuss this with them, and they've pointed out that they don't appreciate me going to our manager with this. (Even though I've tried for over a year to bring it up in person).
Both of them have recently resigned from the company, I assume our team issues are a large cause of this, and I truly feel bad about it. They've mentioned they got tired of me complaining about this, but to me it was a fundamental problem within the team. There were a lot more issues within the company, but to me being in a small team and not being able to work together was one of the biggest issues here.
Since I will continue to work in this country for a while, I'm wondering how I should approach this problem in the future. Should I talk to them in person and make them understand my feelings? Or should I involve my manager straight away in this?