说英语朗读课文尽可能大声的说法是 "read the text aloud as loudly as possible"。
来源："read" 是英语中读的意思；"aloud" 是英语中朗读的意思；"loudly" 是英语中大声的意思；"as possible" 是英语中尽可能的意思。
例句：
"Please read the text aloud as loudly as possible so everyone can hear."
(请尽可能大声地朗读课文，以便每个人都能听到。)
"The teacher instructed the students to read the passage aloud as loudly as possible."
(老师指示学生尽可能大声地朗读这篇文章。)