YOU SAID:

I am the only person who can properly english

INTO JAPANESE

私は適切に英語を話すことができる唯一の人です

BACK INTO ENGLISH

I am the only person who can properly speak English

INTO JAPANESE

私は英語を正しく話すことができる唯一の人です

BACK INTO ENGLISH

I am the only person who can speak English correctly

INTO JAPANESE

私は英語を正しく話すことができる唯一の人です

BACK INTO ENGLISH

I am the only person who can speak English correctly