The body language accompanying speech is the object of study of paralinguistics. This includes gestures, facial expressions, hand movements, even laughter. Apropos of the latter, Americans––like all nationalities––have a culture-specific range of laughter types, with high-pitched, aesthetically unpleasing laughter being especially common among American females (but not only). This acoustic peculiarity is currently coming into alignment with the infantilized intonation and vocal timbre remarked here before. The ensemble of these paralinguistic traits is distinctively and unflatteringly American.
Another distinctively American species of paralinguistic behavior is the habit of not looking at one’s interlocutor when handing the latter an object. This act violates a fundamental (European and Asian) staple of paralinguistic norms, resulting in behavior that risks being interpreted by a non-American (or culturally multidimensional American) conversation partner as decidedly rude.