There are some idioms in English which differ slightly as between American and British versions. Thus, for instance, sweep under the carpet in British English comes out as sweep under the rug in American. Similarly, bat an eyelash in American English corresponds to bat an eyelid in British. Both versions, to be sure, can be heard in both varieties of English, but the preferential forms are as stated.
It is, of course, foolhardy to generalize on the basis of a mere two examples, but the trend is worth noting nonetheless. American English tends to use the paronomastically full-fledged [NOT “fully-fledged!”] version, which involves the repetition of vowels (both stressed and unstressed)––hence the rhyme of American under and rug or bat and eyelash, lacking in the British version.
Whatever the (cultural) cause, even these isolated examples make it irrefragably clear that paronomasia is patently not the exclusive purlieu of poets.
The advent of the sociolinguistic institution known as a standard language no earlier than two centuries ago ushered in an immediately perceptible cultural criterion according to which the accent of a speaker that deviated from the norm acted as a barrier in rising up the socioeconomic ladder. Thus, in a well-known case, British subjects whose speech did not conform to the King’s/Queen’s English––otherwise dubbed “RP” (for “Received Pronunciation”), i. e. the accent of Oxford and Cambridge universities––were routinely ruled out of the competition for places in the foreign service and in positions of authority in government and business circles.
The American situation is somewhat less straightforward. Standard American English (“SAE”) has never been a strict speech requirement for aspirants to high office, witness the recent examples of Jimmy Carter and Bill Clinton, both speakers of a variety of Southern American dialects. For African-Americans, however, SAE is a practically indispensable vehicle in the climb up the class ladder, notably exemplified today by Barack and Michelle Obama (both graduates of Ivy League universities [Columbia and Princeton, resp.] and Harvard Law School). Not speaking in Black English is demonstrably a prerequisite to advancement in most walks of American life save the entertainment industry, where the speech of the criminal underclass may even be the norm in certain genres (like hip hop).
When it comes to foreign accents in America, there is an interesting variegation of the sociocultural picture such that racial and ethnic membership is perceived as a license to deviation from the norm. A prominent example is Henry Kissinger, who has steadfastly maintained his Dr. Strangelove German accent in English, despite having immigrated to the United States as a teenager, and has nonetheless risen to become a Harvard professor and a Secretary of State. This case illustrates the fact that as long as a person’s non-standard American speech cannot be identified phonetically with any native American dialect it need not be an impediment to their socioeconomic ascendancy.
When the sounds /t d s / occur before yod (orthographic y or u), they undergo a phonetic change called palatalization, by which is meant a replacement of the dental stop or dental fricative by a palatal consonant, viz. (respectively) /č dʒ š ž/. Hence, within a word the combination /t/ + /u/, as in mature, is typically pronounced with a [č]; /d/ + /u/, as in adulation, with a [dʒ]; /s/ + /u/, as in usual, with a [ž] (note the intervocalic laxing of s) . This intra-word palatalization can be suspended in hyper-careful pronunciation, which for some speakers is in fact the norm, as in [mətʋr] instead of [məčʋr].
Palatalization generally does not occur across word boundaries, however, with some exceptions. Thus the interjection gotcha, which is a contraction of got you, used to indicate understanding or to signal the fact of having caught or defeated another, is an orthographic rendering of the process of palatalization of [t] before [y].
Similarly, many speakers pronounce the combination this year (in allegro tempo) with a [š] for /s/. In this latter phrase the functional upshot of the phonetic change does not remain at the level of sound. In semiotic terms, it is a change that promotes textual cohesion, since it as an index of the bound character of the two words. The word boundary separating this from year is elided in the process of creating a compound.