From time to time I see “publically” in copy. I’ve even caught myself typing it once or twice. It’s widely regarded as a mistake (although some dictionaries now list it as a variant spelling).
But the approved spelling, “publicly”, is a unique oddity. It’s the only adverb ending in “–icly” formed from an adjective that ends in “–ic”. Compare:
- hectic – hectically
- tragic – tragically
- archaic – archaically
- cryptic – cryptically
- idiotic – idiotically
And so on. But “public” alone bucks the trend to become “publicly”.
At least, it does most of the time. In the GloWbE corpus (a record of language used on web pages archived in 2012), “publically” is about 6% as common as “publicly”. In the Google Books records, it’s below 1%.
People who write “publically” – whether through momentary carelessness or because they think that’s how it’s spelt – may be mistaken but they’re not stupid. They’re promoting regularity in the language. They’re like children who say “runned” and “buyed” and “bringed” because they’ve worked out the rule for forming past-tense verbs but haven’t realised that there are exceptions.
We get taught about these exceptions, though: there are over 100 irregular verbs, most well-known. But there’s only one “publicly”, so people are less aware of it as an issue and it appears in adult usage far more than over-regularised verbs.
I don’t know why “publicly” is unique, but Pam Peters notes that several adjectives have both “–ic” and “–ical” forms. Some of these pairs have pretty much the same meaning:
Some are subtly different in meaning:
Others are more significantly different:
Peters connects this to the adverb situation:
The parity of adjectives in -ic and -ical helps to explain why the adverbs for both types end in -ically. So, for example, the adverbs for organic and tragic are organically and tragically. Even though the -ical forms of the adjectives have long since disappeared, their ghosts appear in the adverbs. The effect is there even for adjectives which never had a counterpart ending in -ical. So barbaric, basic, civic, drastic and others become barbarically, basically etc., and it’s as if -ally is the adverbial ending for them. This has become the general rule for all adjectives ending in -ic except public, whose adverb is still normally publicly.
This is interesting, but it doesn’t tell us why the adverb forms settled as “–ically” rather than “–icly”.
So I looked at the OED historical citations for the 16 bullet-pointed examples above, and found that for 12 of them, the “–ical” form of the adjective pre-dated the “–ic”. This kind of suggests that, if these pairs were interchangeable at the time (1400s–1600s in most of these cases), the “–ical” forms may have been better established and so had a dominant position when it came to forming adverbs. Hence the “–ically” convention.
But this doesn’t tell us why “publicly” now stands alone. It did appear earlier than most of the other adverbs above; the OED’s first “public” is in 1394 and “publicly” 1534. So maybe it had managed to dig in by the time the “–ically” convention was blossoming? The OED has a couple of “publical”s (one in 1450, one in 1898) but they’re clearly rogue; “public” has always been the only accepted form of the adjective, and this fact may have pushed people towards “publicly”. (“Publically” doesn’t appear until 1797.)
A scrap of support for this theory comes from the fact that “publicly” hasn’t always stood alone. The now-dead “franticly”, which Peters mentions, used to be common. The OED’s first “frantic” was in 1390, “franticly” in 1549 and “frantically” in 1749; it has no record of “frantical”. The situation is very like that of “public” and its derivatives, except that “publicly” has managed to survive regularisation.
So far, at least.