by unconscious Phonetic change is particularly common in Compound words. By a phonetic change (§ 122) the final -o- of the first half of compounds like *agro-cola ‘tiller of the fields’ became -ĭ- so that we know the word only as agri-cola.
Thus a type was established for the great mass of compounds, so that we get words like foedi-fragus, ‘treaty-breaking’ from foedus, foederis ‘treaty,’ where logically the first part ought to have been foeder-. Just in the same way in Greek in the very numerous compounds like μῡθολόγος, ‘a teller of ancient stories’ and μῡθολογίᾱ ‘the knowledge of stories, mythology,’ or ἀστρολογίᾱ ‘the knowledge of the stars,’ hence ‘astrology,’ the final -o- of the first part of the word came to be felt as part of the ending; hence new words were made like φυσιολογίᾱ ‘physiology’ from φύσις ‘native power, nature,’ instead of *φυσιλογίᾱ, which would have been correct. Hence in English came the names for the different sciences which are sometimes called the “-ologies.”
§ 20. So it is common in compound verbs to have the form of the simple verb restored. For example in Latin dēlēnio is restored on the pattern of the simple lēnio, instead of dēlīnio which would have been the true phonetic form (§ 129). Such restored forms are called Re-formates.
§ 21. Again by a regular phonetic change (§ 184) claudo became in compounds clūdo (concludo, exclūdo, inclūdo, reclūdo); but these words were so much commoner than the simple claudo that before the time of Juvenal the form claudo had died out altogether,
