What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
Of, relating to, or designating the mental aspects of sound production.
Early 20th century; earliest use found in Transactions of the American Philological Association. From psycho- + phonetic, after Polish psychofonetyczny (J. B. de Courtenay 1894, in Rozprawy Akad. Umiejętności: Wydział Filol 2nd Ser. 5 254. Compare German psychophonetisch.