One recent vowel phoneme in English is /ɜ:/. It would seem that this sound only developed in a certain phonetic environment, or to phrase it differently: it only appeared under certain conditions.
closed as not a real question by simchona♦, Mr. Shiny and New 安宇, Irene, FumbleFingers, Hugo Dec 17 '11 at 20:04
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.