Why English words are not pronounced as they're spelt

Edward Finegan and Niko Besnier, from Language: Its Struc­ture and Use, pp. 34-35.

There are five prin­ci­pal reason for the dis­crep­ancy between the written rep­re­sen­ta­tion of many English words and their actual pronunciation:

  1. English or­thog­ra­phy had several diverse origins with dif­fer­ent spelling conventions:

  2. The system that had evolved in Wessex before the Norman In­va­sion of 1066 gave us such spellings as ee for the sound in words like deed and seen.

  3. The system that was over­laid on the Old English system by the Normans, with their French or­tho­graphic customs, gaves us such spellings as queen (for the earlier cween) and thief (for earlier theef).

  4. A Dutch in­flu­ence from Caxton, the first English printer, who was born in England but lived in Holland for thirty years, gave us such spellings as ghost (which re­placed gost) and ghastly (which re­placed gastlic).

  5. During the Renaissance, an attempt to reform spelling along et­y­mo­log­i­cal (that is, his­tor­i­cally earlier) lines gaves us debt for earlier det or dette and salmon for earlier samon.

  6. A spelling system es­tab­lished several hundred years ago is still used for a lan­guage that con­tin­ues to change and develop its spoken form. Thus the initial k in knock, know, knee, and certain other words was once pronounced, as was the gh in knight and thought, among others. As to vowels, change in progress when the system was de­vel­op­ing and con­tin­u­ing change in pro­nun­ci­a­tion have led to such matched spelling for mis­matched pro­nun­ci­a­tions as beat/great and food/foot.

  7. English is spoken dif­fer­ently in dif­fer­ent coun­tries through­out the world (and in dif­fer­ent regions within a single country), despite a rel­a­tively uniform stan­dard for written orthography. Though this or­tho­graphic uni­for­mity cer­tainly fa­cil­i­tates in­ter­na­tional communication, it also in­creases the dis­par­ity between the way English is written and spoken in any given place.

  8. Words (and their mean­ing­ful subparts) alter their pro­nun­ci­a­tion de­pend­ing on the ad­ja­cent sounds and stress patterns. For example, in electric the second c rep­re­sents the sound [k] as in kiss, but in electricity it rep­re­sents the sound [s] as in silly. Compare also the pro­nun­ci­a­tion of i in senile (pronounced like the i of I’ll) with its pro­nun­ci­a­tion in senility (in which it has the i of ill).

  9. Spoken forms differ from one set of cir­cum­stances to another—for example, in formal and in­for­mal situations. While some degree of such vari­a­tion is in­cor­po­rated into the written system (do not/don’t; was/’twas), there is rel­a­tively little tol­er­ance for such spelling vari­a­tion as gonna (‘going to’), wanna (‘want to’), gotcha (‘got you’), and jeat yet? (‘did you eat yet?’). Such vari­able spelling of vari­able speech would force readers to de­ter­mine the pro­nun­ci­a­tion of the rep­re­sented speech before ar­riv­ing at meaning, instead of di­rectly for meaning, as adult readers nor­mally do, with the ne­ces­sity of silent pronunciation.