1. English has many diphthongal sounds, such as the "oy" sound in "boy" and the "au" sound in "house".
英语中有许多二元音连音，比如"boy"中的"oy"音和"house"中的"au"音。
2. She struggled with the diphthongal pronunciation of certain words in the foreign language.
她在外语中对一些单词的二元音连音发音感到困难。