Comparative linguistics led to a picture of ancient Greek that more or less corroborated Erasmus' view, though with some modifications. It soon became clear, for instance, that the pattern of long and short vowels observed in Greek was mirrored in similar oppositions in other languages and thus had to be a common inheritance (see Ablaut); that Greek had to have been at some stage because it regularly corresponded to in all other Indo-European languages (cf. Gr. : Lat. '); that many instances of had earlier been (cf. Gr. : Lat. '); that Greek sometimes stood in words that had been lengthened from and therefore must have been pronounced at some stage (the same holds analogically for and , which must have been ), and so on. For the consonants, historical linguistics established the originally plosive nature of both the aspirates and the mediae , which were recognised to be a direct continuation of similar sounds in Indo-European (reconstructed and ). It was also recognised that the word-initial "spiritus asper" was most often a reflex of earlier (cf. Gr. : Lat. ""), which was believed to have been weakened to in pronunciation. Work was also done reconstructing the linguistic background to the rules of ancient Greek versification, especially in Homer, which shed important light on the phonology regarding syllable structure and accent. Scholars also described and explained the regularities in the development of consonants and vowels under processes of assimilation, reduplication, compensatory lengthening etc.