Meaning of the word "he teaches ill, who teaches all" in English

What does "he teaches ill, who teaches all" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

he teaches ill, who teaches all

US /hi ˈtiːtʃɪz ɪl, huː ˈtiːtʃɪz ɔːl/
UK /hiː ˈtiːtʃɪz ɪl, huː ˈtiːtʃɪz ɔːl/
"he teaches ill, who teaches all" picture

Phrase

a proverb suggesting that a teacher who tries to cover too much material at once or teaches everyone the same way without focus fails to teach effectively

Example:
Focus on the core concepts first; remember, he teaches ill, who teaches all.
The curriculum is too broad; as the saying goes, he teaches ill, who teaches all.