Like this father,Chinese teachers ...have also found their students' composition,using Internet jargon,difficult to understand.
= 高中老师跟这个父亲一样感到/发现学生所写的作文因为充满了网络语挺难懂.
Like this father 意思是 = Not only this father (the father of this particular student) but also Chinese high school teachers have found their students' composition,using Internet jargon,difficult to understand.= 不但是这个父亲,高中老师也都觉得学生所写的作文因为充满了网络语挺难懂.
find (过去式 found) 在这里是 觉得,感到,发现的意思