157. Differences in accentuation and in the environment of vowels or
consonants regularly developed different stems in different parts of
some verbs. For instance, _ádjūtā́re_ ＞ aidar (§ 45), while _adjū́tat_
＞ aiüda.
158. Sometimes, as above, an intertonic vowel disappeared: _mándūcā́re_
＞ maniar, _mandūco_ ＞ ✱mandüc manüc; ✱_parabolāre_ ✱_páraulā́re_ ＞
parlar, ✱_parabŏlat_ ✱_paraulat_ ＞ paraula. In such cases the shortened
stem usually prevailed: mania, parla. But in _adjutare_ the longer one
was preferred: aiüdar.
159. (1) A vowel which breaks in one part of a verb may be unstressed,
and therefore remain unbroken, in another part: _probāre_ ＞ proar,
_prŏbat_ ＞ prueva,[116] ✱_sequīre_ ＞ sęguir, ✱_sĕquit_ ＞ sięc.[117] In
such cases the phonetic development is generally undisturbed.
(2) A vowel which breaks in one part of a verb may, with different
environment, remain unbroken even in another part in which it is
stressed: ✱_volēre_ ＞ volẹr, ✱_vŏleo_ ＞ vuelh, ✱_vŏlet_ ＞ vǫl. If
the breaking occurs in the 1st pers. sg., the phonetic development is
regularly undisturbed; if it occurs in the 2d and 3d pers. sg., it is
generally carried into the other forms in which the vowel is stressed:
_cŏllĭgit_ ＞ cuęlh, hence cuęlh = _collĭgo_; _ĕxit_ ＞ ięis, hence ięsc,
ięscon, ięsca.
160. A consonant may be followed by e̯ or i̯, and so palatalized, in
one part of the verb, and not in another: ✱_cadeo_ ＞ chai, ✱_cadēmu’_
＞ chazẹm; _dēbeo_ ＞ dẹch dẹi (§ 73, βy), _dēbet_ ＞ dẹu; _faciat_
＞ fassa, _facĕre_ ＞ faire; _fŭgio_ ＞ füi, _fugĕre_ ＞ fugir; _jaceam_
＞ iassa, _jacēre_ ＞ iazẹr[118]; _placeāmu’_ ＞ plassám, _placēmu’_ ＞
plazẹm; _sapiam_ ＞ sapcha, _sapit_ ＞ sap; _tĕneo_ ＞ tenh, _tĕnet_
＞ ten; _valeo_ ＞ valh, _vales_ ＞ vals; _vĕniat_ ＞ venha, _venīre_
＞ venir; _vĭdeam_ ＞ vẹia, _vidētis_ ＞ vezẹtz; ✱_vŏleo_ ＞ vuęlh,
✱_vŏlet_ ＞ vǫl. Verbs in _-eo_ generally keep this distinction; but we
find mǫva, somóna, tẹma = _mŏveam_, _submŏneam_, _tĭmeam_. Most verbs
in _-io_, on the other hand, dropped the i̯ in Vulgar Latin: _partio_
✱_parto_ ＞ part, _partiunt_ ✱_partunt_ ＞ parton, _partiam_ ✱_partam_
＞ parta; sen, senton, senta; sięrf, sięrvon, sięrva; etc. A few verbs
show forms both with and without the e̯ or i̯: _audio_ ＞ auch (_audiam_
＞ auia), ✱_audo_ ＞ au; _crēdo_ ＞ crẹ, ✱_crēdeo_ ＞ crẹi[119]; _vĭdeo_
＞ vẹi[119], ✱_vĭdo_ ＞ vẹ.
161. Verbs in -ng- naturally developed a palatal consonant before e
or i (§ 73, Ng´), but not before other vowels: _cĭngĕre_ ＞ cẹnher,
_cĭngo_ ＞ cẹnc, _cĭngit_ ＞ cẹnh, _cĭngam_ ＞ cẹnga; so fẹnher,
ọnher, plánher, pọnher, etc. The palatal was carried by analogy into
the parts that were originally without it: hence the double forms cẹnc
cẹnh, cẹngon cẹnhon, cẹnga cẹnha, etc. These double forms led
tenẹr, venir to adopt tenc, venc, tenga, venga, beside the regular
tenh, venh, tenha, venha. Such forms as these, supported by dẹrc
＜ _de-ērĭgo_, dic ＜ _dīco_, pręc ＜ _prĕco_, sęc ＜ ✱_sequo_, trac ＜
✱_trago_, etc., afforded a starting-point for an ending -c, adopted
by some other verbs in the 1st pers. sg. of the present indicative:
_pĕrdo_ ＞ pęrt pęrc, _pr(eh)ĕndo_ ＞ pren prenc, _remaneo_ ＞ remanh
remanc, etc.