Singular noun forms that whose spelling ends in a silente form the regular plural with the ending-s. Alternatively, they could be analysed as dropping the silente and adding the ending-es, particularly where the consonant is sibilant and there is an identical verb (which would drop thee before the ending-ing): "a dance"→"some dances" parallels "it dances"→"it is dancing" better under such analysis. This applies to nouns that end ince and(d)ge.
Uniquely in American English, the nonstandard pronunciations ofprocesses (/ˈpɹɒsɛˌsiːz/) andbiases (/ˈbaɪəsiːz/), where-es is pronounced likeease, is due to influence from plurals likeparentheses andhypotheses, and perhaps evenbases.
However,processes is also, unusually, pronounced/ˈpɹəʊ̯sɛsiːz/ in England and/ˈpɹoʊsɛsiːz/ in Canada.
FromMiddle English-es,-is, fromOld English-es,-as, Northern variants of-est,-ast(second person singular indicative ending). Replaced Middle English-eth, fromOld English-eþ,-aþ. The falling together of the second and third person singular verb forms in Old English is believed to be due to Scandinavian influence, where the employment of the same verbal endings for both 2nd and 3rd singular indicative follows a similar pattern to that seen in Old Norse (e.g.þú masar, hann masar; þú þekkir, hann þekkir; etc.).
1573,An exposition of the kinges prerogative, collected out of the great Abridgement of Justice Fitzherbert and other olde writers of the lawes of England, page38:
... whereupon king Henry his sonne, as it may appeare by the later clause of this chapter, recouered diuers eschet[s] of lande within this Realme holden by Normans, whiche after they began to adhere to the French king, the kinges enimy[…]
From*-h₁i-t-, fromProto-Indo-European*h₁ey-, the root ofeō, īre(“to go”). Because the nominative singular would regularly have developed to*-is, the attested ending*-es has to be explained as an analogical replacement based on the alternation between-ĕ- in the closed final syllable of the nominative singular and-ĭ- in the open medial syllable of oblique forms that developed regularly in other nouns as a result of the sound change of vowel reduction.[1]
^De Vaan, Michiel (2008) “comes”, inEtymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill,→ISBN,page129
FromOld Galician-Portuguese-ez, further origins unknown. The preferred options are that it was either an internal innovation (from a reanalysis of the genitive in names ending with-ricus, i.e.-rici, as naming suffix) or a borrowing from pre-Roman languages (given the various forms the suffix took in the Middle Ages). CompareSpanish-ez.
FromLatin-ēs,Latin-is, andLatin-īs, the second-person singular present active indicative endings of second, third, and fourth conjugation verbs, respectively.
Verms whose stems do not end in-s normally take the-s suffix for the passive voice. Until the middle decades of the 20th century (approximately), the norm in writing was to use-es with all-er verbs, but this use is considered archaic today.
R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “-es”, inGeiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies
