orthography - Is there a rule for “‑ance” vs. “‑ence”?

OK, so I’m ashamed to admit that as a native speaker I think I’ve missed something somewhere. I was typing up some documentation and spellchecker kept bugging me. So I looked up some words and found this:

The suffixes ‑ance and ‑ence mean
“quality of” or “state of.” Words
ending in these suffixes are usually
nouns. There is no rule that governs
whether a word ends with
‑ance or ‑ence.

Even the dictionary on my Mac goes so far as to say:

ORIGIN from French ‑ence, from Latin
‑entia, ‑antia (from present participial stems ‑ent‑, ‑ant‑). Since
the 16th cent. many inconsistencies
have occurred in the use of ‑ence and
‑ance.

Is this for real? There really is no rule?

Answer

Yes, this is for real. No, there really is no rule. There used to be a rule in Latin, though. Etymonline explains in more detail:

-ance
suffix attached to verbs to form abstract nouns of process or fact (convergence from converge), or of state or quality (absence from absent); ultimately from L. -antia and -entia, which depended on the vowel in the stem word. As Old French evolved from Latin, these were leveled to -ance, but later French borrowings from Latin (some of them subsequently passed to English) used the appropriate Latin form of the ending, as did words borrowed by English directly from Latin (diligence, absence). English thus inherited a confused mass of words from French and further confused it since c.1500 by restoring -ence selectively in some forms of these words to conform with Latin. Thus dependant, but independence, etc.