[92]. Proclitics are unaccented words which are pronounced as a part of the following word; they are: (1.) The relative and indefinite pronouns and their derivatives; (2.) Prepositions.
([a.]) Thus, quō diē, pronounced quōdíē; quī vīxit, quīvī́xit; genus unde Latīnum, génus undeLatī́num. Similarly quamdíū, as long as; iamdíū, this long time. A distinction is thus made between the interrogative quālis ([1526]), which is accented, and the relative quālis ([1831]) which is proclitic (Quint. 1, 5, 26); cf. the English who, which is accented when interrogative, and proclitic when relative. (b.) circum lītora, pronounced circumlī́tora; ab ōrīs, pronounced abōrīs (Quint. 1, 5, 27); in inscriptions and manuscripts prepositions are often united in writing with the following word. Phrases like extemplō, suddenly, invicem ([94]), in turn, are commonly written and accented as one word. But the preposition is accented when it is followed by a monosyllabic unemphatic (and therefore enclitic) personal pronoun: as, ín mē; ábs tē (but abs tḗ, if tē is emphatic). All prepositions used as adverbs ([1402]) have an independent accent.
[93]. Enclitics are words which have no accent of their own, but are pronounced as a part of the word preceding. This increase of the number of syllables produced certain accentual changes, all the details of which are not clear. When the enclitic was monosyllabic the place of the accent seems to have been determined as in [86]; thus vídēs, but vidḗsne; Látiō, but Latiṓque. Again, when by the addition of a monosyllabic enclitic the accent falls on the fourth syllable from the end, a secondary ([84], [85]) accent was probably placed on the penult: as, perī́cula, but perī́culàque. The Roman grammarians agree, however, in demanding that everywhere the syllable preceding the enclitics -que, -ne, -ve, and -ce should be accented. In deinde and subinde there is authority for placing the accent on the first syllable.
Enclitics are: (1.) Unemphatic personal and indefinite pronouns: as, in mē, pronounced, ínmē; dā mihi, dā́mihi; sīc tibi, sī́ctibi; sī quis, sī́quis; nē quid, nḗquid. (2.) Verbs when used as auxiliaries: as, possum for pót(e) sum ([752]); quī́ libet ([2401]); vidḗlicet, īlicet, scīlicet ([712]); quámvīs ([1903]); the forms of esse in compound tenses ([719]), so that est is frequently combined, even in writing, with the preceding past participle ([747]). (3.) The particles -ne (-n), -ve, and -ce (-c): as, satísne or shortened satín; Hyrcānīsve Arabī́sve; istī́ce or shortened istîc ([90]), adhûc ([90]). (4.) The copulative conjunction -que: as, Latiṓque, līmináque. (5.) The preposition cum when it follows ([1435]) its case. (6.) The particle quidem: as, sī quidem, síquidem ([131]). ([7.]) Other enclitics are: -met ([650]): as, egómet; -dem: as, ibídem; -nam: as, ubínam; -dum ([1573]): as, agédum; -inde: as, déinde, próinde (which are disyllabic in verse), and súbinde; -tum; as, etiámtum; -per: as, parúmper; the vocative when it was closely joined to the preceding word, e.g. an imperative: as, dī́c puer ([106]).
[94]. Two words expressing what is really one single idea are often bound together by one accent, one of them acting the part of either a proclitic or enclitic.
Thus, with the earlier recessive accent ([89]), Iū́piter ([133]; [389]; originally a vocative which came to be used as nominative; for the change of pater to piter see [104]); ínvicem, in turn; dḗnuō for dḗ nóvō ([106]); with the later, classical accent, lēgislā́tor, paterfamíliās, orbisterrā́rum, extémplō, imprī́mīs. When unemphatic ille and iste preceded their noun and had practically the value of our definite article they formed a unit with the following noun and thus the accent might fall on their last syllable: as, illé pater, isté canis. This use is particularly common in vulgar and late Latin (see [112]).
[CHANGE OF SOUND.]
[(A.) VOWEL CHANGE.]
[CHANGE OF DIPHTHONGS IN ACCENTED SYLLABLES.]
[95]. Of the six original diphthongs au, ou, eu, and ai, oi, ei, the only one which preserved its original sound in the classical period is au. Of the rest only ae (for older ai) and, in a few words, oe (for older oi) remained diphthongs; all the others had become monophthongs.