尊敬語 => Honorifics N4
を中心に => focused on; centered on~ N2
丁寧語 => polite form N4
謙譲語 => Humble form N4
…のも無理 (は) ない => It's natural for... N3
Evaluate
のも無理もない => (to be) natural,(to be) understandable N3
Evaluate
と言う/と言っていた => you could say; one might say; I'd say ~ N5
は..語で何ですか => What does it mean... N5
Explain
[中心「ちゅうしん」]に => With A as the center N2
Miscellaneous
と言っている => To say that ... N3
Speaking
と言っていました => Someone said... N4
Speaking
と[言「い」]うのは => Means, is N3
Information, Report