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

Other sounds:

aspirated forms of all stops
/l/ is velarized
bilabial and dental/alveolar voiced implosives
/a/ is fronted
certain vowels are long, others are short
a is fronted

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