If you watch the first video you will see that these are famous Indian people from different Indian ethnicity and you will find some similarity in their accent irrespective of whether they are from south or north India. The way they stress on some alphabets and pronounce some words are very much similar and seem different/unique as compare to those belong to different race say Chinese or African .In UK we have Scottish, welsh, Irish people who had different accent of English than those who live in England . British born Indians also don't have same accent than those who live in India even though they both belong to same race but because English is first language of these British born kid that's why they sound different when speak English. If PC was British/American born and had made this music album then i don't even bother to criticise her because then she would have English as her first language and we know everyone feel more comfortable singing in their native/first language which is original and come naturally without the need of acting or faking yourself