1. At the end of monosyllables with a short vowel sound, the letters
_f_, _l_, or _s_ are usually double; _e.g._, muff, ball, pass.
2. Words ending in silent _e_ usually drop it on adding any suffix
beginning with a vowel; _e.g._, come, coming; bride, bridal; love,
lovable.
EXCEPTIONS:--(i) Words ending in _ce_ or _ge_ retain the _e_ before
the suffixes _able_ and _ous_, in order to keep the soft sound of _c_
or _g_; _e.g._, traceable, outrageous.
(ii) Words ending in _ee_, _oe_, or _ye_ retain the final _e_ when
_ing_ is added; _e.g._, freeing, shoeing, eyeing.
3. Monosyllables and words accented on the last syllable, if they end
in a single consonant with a single vowel before it, usually double
the final consonant before a vowel-suffix, _e.g._, clap, clapper;
clan, clannish; nod, nodded; prefer, preferring.
EXCEPTION:--When the derivative has the place of the accent changed,
the final consonant is not doubled; _e.g._, prefer´, pref´erence.
Note also, _gases_, _gaseous_, _transferable_, _woolly_.
4. Words ending in a single _l_ double it before a vowel-suffix;
_e.g._, chisel, chiselled; revel, reveller; cancel, cancelling. But,
_paralleled_.
5. Words ending in _y_ preceded by a consonant usually change the _y_
into _i_ when a suffix not beginning with _i_ is added; _e.g._, cry,
cries, crying.
EXCEPTIONS:--Dryly, dryness; shyly, shyness; slyly, slyness.
Note also daily, gaily, gaiety, laid, paid, said, saith, slain, staid.
6. _ei_ or _ie_. When sounded like long _e_, _i_ comes before _e_
except after _c_; _e.g._, piece, deceit. But, _either_, _neither_,
_plebeian_, _seize_, _leisure_, _weird_.
When not sounded like long _e_, the order of the letters is always
_ei_; _e.g._, skein, height.