What does that even mean? Have you tried pronouncing any Khoisan languages (or other languages with clicks) for example? If your native language is English, you'll have a much harder time than a native Zulu speaker would have.

Whether a target language is easy to pronounce depends on your native language (and other languages you can pronounce accurately). If you're a native Chinese speaker (whichever variety, but particularly Mandarin), English isn't anything like as difficult as French to pronounce.

Question: Are you referring to the spelling<->phonetic consistency of the language or to the sounds the language use? I think you and tokenadult may be speaking about different things here.