*novenos); but it was changed to novem so as to match septem and decem in which -m was original (cf. Lat. septimus, decimus: Sansk. saptamas, ‘seventh’; daçamas, ‘tenth’),
§ 15. Very often these Analogical changes modify the results of a Phonetic Law and so produce apparent exceptions to it. In Latin in words of two syllables (‘Disyllables’) whose first syllable was short like via and modus, the second syllable of the Ablative was shortened by a phonetic change (§§ 95, 96). But in words like dominus and mensa which had more than two syllables, or a long first syllable, this phonetic change did not take place, so that the abl. remained mensā, dominō: and these words were far more numerous than the words of the shape of via, modus.
Hence people felt that in the First and Second Declensions the meaning of the abl. required -ā or -ō to express it properly: and so they would not allow themselves or their children to pronounce anything but a long vowel in the Abl., even of words like via or modus. We state this process shortly by saying that the -d in via and the -ō in modō were “restored by Analogy.”
§ 16. But meanwhile the word modo had come to be used not only as an ablative meaning ‘by’ (or ‘on’) ‘the proper line’ but as an adverb meaning ‘just, only’: and in this meaning it was no longer felt by the general body of speakers, or as we say ‘in the popular consciousness,’ to be an ablative. Hence in the adverb the short -o produced by phonetic change was left unaltered. Exactly the same phonetic
