Singers around the world idolize American pop music and American pop artists. So much so that they will often model their music after theirs and sing half (often the hook/ chorus) of their song in English and half (the verses) in their home language. There is a unique challenge for non- American pop singers.
1. English is not their native language
2. Their dominant language is often full of sounds that do not translate well into singing as well as the home language is often does not 'sing' well.
 English is an easier language for them to sing in which is why international pop singers choose to sing their hooks or choruses in English.. it just 'sounds' better. Often times the home language,however, carries with it habits that are contrary to good singing and are hard to overcome. Take for example, Asian languages, such as Chinese, Japanese, or Indonesian, these languages produce tight, throaty vowels. It is hard and awkward to sing on these vowels but broadening the vowel may make the word sung sound awkward. Also, when these singers sing in English, they 'sound' un-American because they carry over the 'tight, throaty' sound of their home language.

Additionally, there is a cultural phenomenon occuring with non -American pop singers. In Japan, for example, it is considered rude and uncouth for a woman to have a full rich voice. Women are then forced (for lack of a bettter word) to speak with a soft, throaty, small, whispery voice so as not to offend those around them. These women grow up to never know the true sound of their voice and when they wish to sing they only know the true sound of their voice and when they wish to sing they only know how to produce a tight small sound, however undesireable. This is a huge task for a vocal coach to
1. allow the woman to be comfortable enough producing a huge sound
2. get her accustomed to the sound of her own voice
3. make the 'big' sound become a habit, because without it she'll never be a successful pop singer.

Let me know your thoughts!!