Because the lessons were conducted in English, English was a familiar language for me.
Because the classes were taught in English, English was something close to me.
ご質問ありがとうございます。
① "Because the lessons were conducted in English,"＝「レッスンは英語で行われていたので」
"English was a familiar language for me."＝「英語は身近（な言語）であった。」
② "Because the classes were taught in English,"＝「授業は英語で教えられていたから」
"English was something close to me."＝「英語は私にとって身近なものであった。」
ご参考に。
アメリカ合衆国 
