言い換える and 繰り返す: rephrasing and repeating
Compare replacing a technical term with everyday wording and repeating words for pronunciation practice. A request for more polite wording asks for a change in expression.
Putting the content differently
言い換える (いいかえる) means rephrasing the core content. In 「難しい専門用語を日常の言葉に言い換えた。」, a difficult technical term was rephrased in everyday language.
「この表現をもっと丁寧に言い換えてください。」 asks for the expression to be rephrased more politely. Making terminology accessible and making an expression more polite are different purposes for rephrasing.
Repeating words or movements
繰り返す (くりかえす) means repeating words or actions. 「発音を覚えるまで同じ言葉を繰り返す。」 describes repeating the same words until their pronunciation is learned.
In 「波は寄せては返す動きを静かに繰り返していた。」, the waves were quietly repeating their movement toward and away from the shore. The repeated object can be a movement as well as words.
Practice frequency and changed wording
Saying a word many times for pronunciation practice differs from changing its expression. Look for a change in wording rather than using the number of repetitions to choose the verb.
Politeness alone does not distinguish these verbs: polite words can be repeated unchanged. A request to rephrase also does not report that the change has already been made.
Does 「この表現をもっと丁寧に言い換えてください。」 ask for more repetitions of the same words?
Show the answer and why
No. It asks for the same content to be expressed more politely. It neither asks for pronunciation repetitions nor reports that the wording has already been changed.