Source of the picture:
"Of course when one of these grand mountain ranges goes stretching across the printed page, it adorns and ennobles that literary landscape -- but at the same time it is a great distress to the new student, for it blocks up his way; he cannot crawl under it, or climb over it, or tunnel through it. So he resorts to the dictionary for help, but there is no help there. The dictionary must draw the line somewhere -- so it leaves this sort of words out. And it is right, because these long things are hardly legitimate words, but are rather combinations of words, and the inventor of them ought to have been killed. [...] Freundschaftsbeziehungen" seems to be "Friendship demonstrations," which is only a foolish and clumsy way of saying "demonstrations of friendship." "Unabhaengigkeitserklaerungen" seems to be "Independencedeclarations," which is no improvement upon "Declarations of Independence," so far as I can see." (Twain, 307)
"I would do away with those great long compounded words; or require the speaker to deliver them in sections, with intermissions for refreshments. To wholly do away with them would be best, for ideas are more easily received and digested when they come one at a time than when they come in bulk. Intellectual food is like any other; it is pleasanter and more beneficial to take it with a spoon than with a shovel." (Twain, 310)
(Twain, Mark. A Tramp Abroad. 1880. Mineola: Dover Publications, 2002)
One of the ways in which a language may enlarge its vocabulary is by putting together two or even more already existent words in order to create aa new word. This phenomena so typical for the German language is commonly termed compounding. Of course, the English language also makes use of this case of word-formation. As a matter of fact, "no known language is without compounds, and in many languages compounds are the main type of new lexemes." (Bauer 1988, 34)
A compound contains at least two root morphemes like in girlfriend and red-hot, and may include affixed forms and prepositions, as in undertaker or mother-of-pearl. The two or more lexemes constituting a compound may either fall into the same grammatical category, e.g. web site (two nouns), or into different categories, like in online (a preposition and a noun).
When two lexems produce a new word through compounding, their combined meaning can be endocentric or exocentric.In the first case, the meaning is suggested by the combination of the words, e.g. milkbottle is a bottle for milk. As the term exocentric suggests, the meaning does not come from within but is created through an exterior element (e.g. cultural associations). For example, highbrow does not simply describe a person with a high brow. Rather, we use it to describe something/someone as intellectual or associated with high culture.
Whether a compound is spelled with hyphens, with a space or no space between the words is not regulated by general rules but idiosyncratic in the English orthography.