But in general, labiodental stops are not used in the world's languages.
‘None of this is true about labiodental flaps,’ Dr. Ladefoged said in an e-mail message.
The labiodental flap is described this way: ‘a buzz sometimes capped by a faint pop.’
There is a small error in the New York Times article on the addition of a symbol for the labiodental flap to the International Phonetic Alphabet that Geoff mentioned: the bilabial trill does not still await its day.
You may have had some problem with the words you have listed, (mostly labiodentals ) while you developed speech, which led to a psychological block making you pause awhile before saying them.
The visual information is especially helpful with front phonemes whose articulation we can see, such as labiodentals and bilabials.
English has only fricative labiodentals , and no stops.
I am particularly interested in the acquisition of Dutch labiodentals , which can be a difficult contrast for German and English learners of Dutch.
An internal origin for these labiodentals is further supported by their distribution on the social variables of age, proficiency, and formal Spanish instruction.