There aren't as many vocal inflections in Japanese as there are in English
Japanese has less changes in intonation compared to English.
この場合ですと「音声変化」は英語で inflection もしくは vocal inflection と言います。
文法用語のinflection もあるので、ご注意ください。
日本語では英語のような音声変化はあまり起こらない - There aren't as many vocal inflections in Japanese as there are in English もしくは Japanese has less changes in intonation compared to English.
イギリス 
