A long time ago I was interested in finding out what the intersection of all languages sounds would be, would it be an empty set or was there enough overlap that someone designing the next esperanto could build it using universal sounds thus allowing any human speaker to pronunciate it without difficulty. Turns out there is a good degree of overlap if you allow for a very small bit of fuzzyness. For instance, 'a','m', and 'p' are some of the most common sounds across all languages, which is also interesting when you realize "mama" and "papa" - with slight variations - display high universality in their pronunciation across all languages.
for more info see: https://www.quora.com/What-are-the-most-common-phonemes-amon...