Return (Retrun) to English

After so many days of job interviews and communicating with foreigners, I've finally come to realise (konw) that I must learn English well, (then) before other languages, because it (.Cause English) is the most International language in the world now.
I hope I can be a good learner,and be able to use this tool freely and confidently as well as (. confidencely. Hope to) make many foreign friends.

Cause and because are two separate words. Because is correct here as it means 'the reason why'.

Retrun to English

After so many days of job interviews and communicating with foreigners,I've finally come to  the realization  that I must learn English well,then other languages. because  English is the most International language in the world now.
Hope I can be a good learner,and be able to use this tool freely and confidently. 
Hope to make many foreign friends.

Good luck Zeta.