I heard that even native English speakers have difficulty in understanding English with strong accent.
I heard it is difficult for even native English speakers to get people who has strong accent in English.
native English speakers : 英語ネイディブの人
have difficulty in :~しづらい
have trouble in : ~しづらい
It is difficult for A to B : ＡがＢするのは難しい
strong accent : 強い訛り
この辺を混ぜてあげて文章を作ってみました！
2番目の文章はよく教科書にも載っている文法でなじみがあるかもしれません！
日本 
