I am wondering if there is a significant difference in frequency of use of vowels in Vietnamese language. This could really help beginning learners like myself who are overwhelmed by the number of phonetic pronunciations and who receive sms messages missing accent marks.

For example, which of the following phonetic pronunciations of "a" used most frequently? Can they be ranked? Are there some that are used so infrequently that they would rarely be seen in common communication? If someone could create a table ranking the vowels as frequent, not frequent, rarely used.

Also it would be helpful to understand if there is a common sequence - a common preceding letter or following letter.

Maybe this has already been done so if someone could point me to a resource that would be great.

á,à,ả,ã,ạ,ă,ắ,ằ,ẳ,ẵ,ặ,â,ấ,ầ ,ẩ,ẫ,ậ

or

é,è,ẻ,ẽ,ẹ,ê,ế,ề,ể,ễ,ệ

or

í,ì,ỉ,ĩ,ị

or

ó,ò,ỏ,õ,ọ,ố,ồ,ổ,ỗ,ộ,ơ,ớ,ờ,� �,ỡ,ợ

or

ú,ù,ủ,ũ,ụ,ư,ứ,ừ,ử,ữ,ự