9 hours ago, Serin O said:

now we are trying to extend our partners internationally.

Already built some partnership with Japan game industries,

what I wonder is - how I can start in English speaking industries.

These days I made very long mail lists and sending studio portfolio & cover letters to industries.

Sometimes get positive answers, but it doesn't feel like productive enough.

Is there some websites like Indeed or LinkedIn for outsourcing studio like us?

Serin, it takes time to build a reputation. You have been doing it right and you should keep on doing what you're doing, but also start investing in networking at international conferences and trade shows. Yes, you should set use LinkedIn - that is for the persons, not businesses, but businesses use it to connect. You can also buy ads on sites like gamedev.net and gamasutra.com and kotaku.com and gamesindustry.biz. Of course your company already has a website, with lots of info about the games you've worked on and the companies you've done business with. You can also create a blog to update followers on your progress. Good luck.