Prescriptive grammarians, castigating various commonly used phrases of a vernacular language, run the risk of encouraging hypercorrections. Hypercorrections are the solecisms introduced into human speech by the strain of the effort made to avoid some form that the prescriptivists have forbidden.

Told to avoid using you and me as the nominative case (e.g. in "You and me are going..."), people will avoid the phrase you and me even when it appears in the oblique case, and will end up saying things like, "Between you and I..." Similar confusion surrounds the pronoun whom; people assume that whom is the formal and fancy version, and end up saying things like "Whom might you be?"

Told that they should never "drop" the ending -ly from adverbs, people produce new words like thusly, soonly, and fastly. Spurious adverb forms also appear behind words that are serving as a copula, and thus would call for a simple predicate in traditional grammar: "my eyes are going badly".

Another area of hypercorrection involves Greek and Latin looking words like octopus; the spurious plural octopi likens the octopus to a number of Latin words that form irregular plurals in -i. (Were there actually a classical plural of octopus, it would be octopodes.) Platypus, cactus, status, hiatus, rebus, syllabus, mandamus, and caucus are sometimes inflected the same way; none would be inflected that way in Latin or Greek. Virus sometimes gets the even more inappropriate pseudoclassical plural form virii, which presumes Latin *virius, and would pluralise bus as bi. All of these words take the regular English inflection in -es, but a few of the hypercorrected forms, such as cacti, have passed into such common usage as to be considered acceptable by some, despite their origins.

When pronunciation of learned words goes astray, it is sometimes called a hyperforeignism. For example, someone might assume, upon learning that the -s is silent in Mardi Gras, that coup de grâce is pronounced "coo de grah".

Another kind of hypercorrection arises when people try to use accents from foreign languages, often adding them spuriously. For example, one often sees habañero peppers, which should be habanero, as a consequence of a misapplied analogy with jalapeño.

Hypercorrection in other languages

Modern Cantonese is currently undergoing a phonological shift, one of the changes being the dropping of the initial ng- (IPA: ) consonant to a null initial. For instance, the word ngaa4 (牙, meaning "tooth"), ends up being pronounced aa4 (Note: Cantonese romanization provided using Jyutping). Prescriptivists tend to consider these changes as substandard and denounce them for being "lazy sounds" (懶音).

However, in a case of hypercorrection, some speakers have started pronouncing words that should have a null initial using an initial ng-, even though according to historical Chinese phonology, only words with Yang tones (which correspond to tones 4, 5, and 6 in Cantonese) had voiced initials (which includes ng-). Words with Yin tones (1, 2, and 3) historically should have unvoiced or null initials. Because of this hypercorrection, words such as the word oi3 (愛, meaning "love"), which has a Yin tone, are pronounced by speakers with an ng- initial, ngoi3.