Obsolete, and dialectic words may be used in moderation, if plainly
marked and accessible in some standard dictionary, such as
Webster’s New International (Merriam’s), Funk & Wagnalls’ and
Century.
Foreign words that are more or less familiar and are easily
accessible, may be used, but should be marked with the language to
which they belong.
Technical terms that are found in a standard dictionary may be
used.
Abbreviations, prefixes and suffixes, should be avoided as far as
possible. When used they should be plainly marked and must be
legitimate.