I wonder if someone told him they didn't like the way he talked.
I wonder if someone said something to him about his odd speech patterns.
この場合、次のような言い方ができますよ。
ーI wonder if someone told him they didn't like the way he talked.
「誰かが彼の話し方が嫌だって彼に言ったのかなあ」
the way he talked「彼の話し方」
ーI wonder if someone said something to him about his odd speech patterns.
「誰かが彼に彼のおかしな語調について何か言ったのかなあ」
his odd speech patterns「彼のおかしな語調」
ご参考まで！
I wonder why the teacher changed the way he talked. Perhaps maybe someone told him they disliked the way he talked.
ご質問ありがとうございます。
この場合、「[誰か](https://eikaiwa.dmm.com/uknow/questions/46534/)が先生にその話しかたが嫌だって言ったんじゃない」と言いたいなら、英語で「I wonder why the teacher changed the way he talked. Perhaps maybe someone told him they disliked the way he talked.」と言えます。
ご参考になれば幸いです。
カナダ 
アメリカ合衆国 
