We say something in the sky.
Have you heard of this "空で言う"?
It literally means "we say something in the sky", but it means "we memorize something like a script and say without looking it. "
Some Japanese might use this, but almost all people use "覚える" and "暗記する".
"覚える" and "暗記する" are more commonly used than "空で言う" everyday speech.
