e (i, eo) .. a (ae, ea) .. u (o):--
_bindan_ (inf.), _band_ (pret.), _bundon_ (they bound). _beran_ (inf.),
_baer_ (pret.), _boren_ (past partic.). _[.c]eorfan_ (cut), _[.c]earf_
(pret.), _curfon_ (they cut), _corfen_ (past partic.). _b[e,]nd_ (bond) =
mutation of band, _byr-then_ (burden) of _bor-en_.
a (ae, ea) .. [=ae]:--_spraec_ (spoke), _spr[=ae]con_ (they spoke),
_spr[=ae][.c]_ (speech).
a .. [=o]:--_faran_ (to go), _f[=o]r_ (pret.), _f[=o]r_ (journey).
_[.g]e.f[=e]ra_ (companion) mutation of _f[=o]r_.
[=i] .. [=a] .. i:--_wr[=i]tan, wr[=a]t, writon, [.g]e.writ_ (writing,
_subst._). _(be).l[=i]fan_ (remain), _l[=a]f_ (remains), whence by mutation
_l[=ae]fan_ (leave).
[=e]o ([=u]) .. [=e]a .. u (o):--_[.c][=e]osan_ (choose), _[.c][=e]as,
curon, coren_. _cys-t_ (choice). _(for).l[=e]osan_ (lose), _l[=e]as_
(loose), _[=a].l[=i]esan_ (release), _losian_ (to be lost). _b[=u]gan_
(bend), _boga_ (bow).
We see that the laws of gradation are most clearly shown in the conjugation
of the strong verbs. But they run through the whole language, and a
knowledge of the laws of gradation and mutation is the main key to O.E.
etymology.
It is often necessary to supply intermediate stages in connecting two
words. Thus _l[e,][.c][.g]an_ (lay) cannot be directly referred to
_li[.c][.g]an_ (lie), but only to a form *_lag_-, preserved in the
preterite _lae[.g]_. So also _bl[e,]ndan_ (to blind) can be referred
only indirectly to the adjective _blind_ through an intermediate
*_bland_-. Again, the root-vowel of _byrthen_ {7} (burden) cannot be
explained by the infinitive _beran_ (bear), but only by the past
participle _[.g]e.boren_. In the same way _hryre_ (fall _sb._) must be
referred, not to the infinitive _hr[=e]osan_, but to the preterite
plural _hruron_.
The vowel-changes in the preterites of verbs of the 'fall'-conjugation
(1) _feallan_, _f[=e]oll_, &c., are due not to gradation, but to other
causes.