Even if the country one visits doesn't have English as their national language, English is still useful.
Because whichever the country, there are always people who can speak English.
ご質問ありがとうございます。
"Even if the country one visits doesn't have English as their national language,"＝「訪問する国の母国語が英語では無くても」
"English is still useful."＝「英語は便利です。」
"Because whichever the country,"＝「なぜかというと、どの国でも」
"there are always people who can speak English."＝「英語を話せる人はいつもいるので。」
ご参考に。
アメリカ合衆国 
