On African-American Vernacular English: Perhaps the more accurate term for this topic nowadays is "urban American English," because other minority groups such as Hispanics have also adopted this version of English, especially in cities. Common characteristics of AAVE include a heavy use of slang (or idioms), with special emphasis given to contractions and subject-verb disagreements. For example, the mainstream American English sentence "they are having fun" would most certainly translate into AAVE as "they is havin' fun." In many ways, AAVE is merely a "bare-bones" version of mainstream American English, especially since it attempts to rid the language of silent letters. Linguistically, however, AAVE shares a lot of phonological similarities with English dialects spoken in the American South. One popular theory is that AAVE originated from the linguistic mixing (creoles and pidgins) which occurred during the Trans-Atlantic slave trade. And because cities served as zones of exchange, where various peoples would assemble to trade goods, linguistic heterogeneity often ensued. Yet even though the South did not experience much urbanization till after the Civil War, AAVE still flourished.
On the Steam Engine: As one of the greatest innovations in engineering history, the steam engine marked the first practical way of converting heat into mechanical work. Of course, people had been boiling water to generate mechanical motion for thousands of years prior to the 1700s, but no single device had yet standardized the process. In 1712, English inventor Thomas Newcomen built the first usable steam engine. Since Newcomen had a background in ironmongery, he had a vested interest in designing and selling specialized tools to miners. One big problem that miners faced in the early 1700s was excess water (which frequently flooded mine tunnels). Thus, Newcomen's engine became the primary pumping mechanism for getting excess water out of (coal and tin) mines. Unfortunately, Newcomen's engine was not very efficient, which prompted Scottish innovator James Watt (and his English business partner Matthew Boulton) to improve it. By the mid-1770s, Watt had successfully doubled the steam engine's (fuel) efficiency, and became the de facto "godfather" of modern engineering. Because Watt recognized a problem, developed a series of potential solutions, and settled on an effective improvement, he embodied the true essence of what it meant to be an "engineer" (instead of just an inventor).
