these are the sounds found in most native Vietnamese dialects:
there are also sounds not on the chart

Other sounds:
labio-velar central approximant [w]
bilabial voiced implosive
alveolar voiceless aspirated stop [th]
alveolar voiced implosive
velar lower mid central approximant
/a/ is long; all other vowels are short

(from: Maddieson, I. 1984. Patterns of Sounds. Cambridge: Cambridge University Press.)