Psilosis is the sound change in which Greek lost the consonant sound pronounced as //h// during antiquity. The term comes from the Greek Greek, Ancient (to 1453);: ψίλωσις psílōsis ("smoothing, thinning out")[1] and is related to the name of the smooth breathing (ψιλή psilḗ), the sign for the absence of initial pronounced as //h// in a word. Dialects that have lost pronounced as //h// are called psilotic.
The linguistic phenomenon is comparable to that of h-dropping in dialects of Modern English and to the development by which pronounced as //h// was lost in late Latin.
The loss of pronounced as //h// happened at different times in different dialects of Greek. The eastern Ionic dialects, the Aeolic dialect of Lesbos, as well as the Doric dialects of Crete and Elis, were already psilotic at the beginning of their written record.[2] In Attic, there was widespread variation in popular speech during the classical period,[3] but the formal standard language retained pronounced as //h//. This variation continued into the Hellenistic Koine.[4]
Alexandrine grammarians codified Greek orthography during the 2nd and 1st centuries BC and introduced, among other things, the signs for the rough (῾) and smooth (᾿) breathings, to make the distinction between words with and without initial pronounced as //h//. However, they were evidently writing at a time when this distinction was no longer natively mastered by many speakers. By the late Roman and early Byzantine period, pronounced as //h// had been lost in all forms of the language.[5]
The loss of the pronounced as //h// is reflected in the development of the Greek alphabet by the change in the function of the letter eta (Η), which first served as the sign of pronounced as //h// ("heta") but then, in the psilotic dialects, was reused as the sign of the long vowel pronounced as //ɛː//.
In the polytonic orthography that started in the Hellenistic period of Ancient Greek, the original pronounced as //h// sound, where it used to occur, is represented by a diacritic (῾), called the rough breathing or spiritus asper. This sign is also conventionally used in analogy to the Attic usage when rendering texts from the Ionic dialect, which was already psilotic by the time the texts were written. For Aeolic texts, however, the convention is to mark all words as non-aspirated.[6]