ABBA, iPad, e e cummings, Schadenfreude: a strange list of words, but one thing they have in common is an unconventional approach to capitalization.
English speakers assume that having small letters and capitals is a natural state of affairs, but many languages, including classical Latin and languages with non-alphabetic scripts, don’t have such a distinction. The Romans had one style for inscriptions in stone, which gave our capitals, and another for handwriting, which gave our small letters, but they were never combined in the same text. Gradually, capitals were introduced into normal text to emphasize, for example, nouns, proper names, and the first word of the sentence.
English no longer capitalizes all nouns, whereas German does. For this reason German nouns borrowed into English are often written with a capital letter. Examples in the Cambridge dictionary include Schadenfreude, a feeling of pleasure when something bad happens to someone else, and Realpolitik, a type of politics that is decided more by the urgent needs of the country than by moral principles. This rule is often ignored for German words that are more integrated into English, like rucksack and strudel.
When printing began, printers kept their type in two cases, or drawers: capitals in the upper case and small letters in the lower case. This is the origin of our terms upper case (usually uppercase in US English) and lower case (US lowercase).
English uses capital letters for the first word in a sentence and for proper nouns. Unlike most other European languages, it also capitalizes the first-person singular pronoun (I) and adjectives that derive from proper nouns:
the Darwinian theory of evolution
Sidewalk is the American word for “pavement”.
Having the choice of two cases has been an irresistible source of variety for marketing people trying to make their products stand out by styling names with unusual combinations of upper and lower case.
For example, all capitals: ABBA (or ᗅᗺᗷᗅ, to be precise), the Swedish pop group; IKEA, the Swedish furniture store. These names draw attention to themselves, by seeming to shout at you.
Or all lower case, for example lowercase, a band from the West Coast of the US. The intention here is to appear younger, fresher, and more relaxed, partly because of breaking the “rule”, and partly because their website’s URL will also have this form.
Sometimes upper case is used in the middle of a word where it would not normally be expected. This is called incapping or camel case. Examples are eBay, iPad. The name camel case comes from the shape of a camel’s back with a hump in the middle.
Marketers were not the first to adopt incapping and unconventional capitalization. Scottish surnames make use of incapping: McIntosh, MacDonald, MacGregor. (Mac is the Gaelic word for “son”.) Apple strangely dropped the incapping on its Macintosh computers, but fast food chain McDonald’s sticks firmly to it. The 20th-century poet e e cummings even made outlandish typography his trademark: