Is there a term for the silent letters in a word?

Solution 1:

Wikipedia references linguist Edward Carney's (Senior Lecturer in Phonetics at the University of Manchester) A Survey of English Spelling in this explanation on silent letters, so the names of these various terms are not standardized. He distinguishes between two types of 'silent letter': auxiliary and dummy:

• Auxiliary letters, paired with another letter, constitute digraphs which represent a single distinct sound. These auxiliary letters are further classified into exocentric digraphs—where the collective sound of the digraph is different from the individual sound of each of its two letters. The individual letters are rarely considered silent because each letter contributes to the overall sound of the digraph. There are two categories of exocentric digraph:

  1. a phoneme with no single-letter representation, such as in consonants 〈ng〉 for /ŋ/ as in sing, 〈th〉 for /θ/ as in thin or /ð/ as in then, diphthongs 〈ou〉 in out or 〈oi〉 in point.
  2. a single-letter representation of a phoneme replaced with a digraph instead, such as 〈f〉 replaced by 〈gh〉 in enough or 〈ph〉 in physical

  —and endocentric digraphs, where the sound of the digraph is the same as that of one of its letters, which are classified into three groups:

  1. most double consonants, as 〈bb〉 in clubbed (but not geminate consonants, as 〈ss〉 in misspell because both s's contribute to the elongated /s/ phoneme)
  2. the discontiguous digraphs, whose second element is "magic e" (silent 〈e〉) , e.g. 〈a_e〉 in rate, 〈i_e〉 in fine
  3. others, such as 〈ck〉 (which is in effect the "doubled" form of 〈k〉); 〈gu〉 as in guard, vogue; 〈ea〉 as in bread, heavy, etc.

• Dummy letters are letters that have no relation to neighboring letters and no correspondence in pronunciation, and are classified into two groups:

  1. inert letters, which are sounded in a cognate word: e.g. 〈n〉 in damn (〈n〉 is pronounced in damnation); 〈g〉 in phlegm (〈g〉 is pronounced phlegmatic); 〈a〉 in practically (〈a〉 is pronounced in practical)
  2. empty letters, which never have a sound, e.g. 〈w〉 in answer, 〈h〉 in Sarah, 〈s〉 in island, 〈b〉 in subtle, the 〈t〉 in ballet. These are the "truest" form of silent letter.

Other forms of silent letters:

• consonant cluster silent letters: silent 〈th〉 in asthma

• spurious silent letters: silent letters that are added to adopted words post factum to more accurately reflect even earlier origins, such as

  • silent 〈b〉 in debt and doubt (from French dette, doute) was inserted to match Latin cognates like debit and dubitable
  • silent 〈s〉 inserted in isle (Norman French ile, Old French isle, from Latin insula; cognate to isolate) and then extended to the unrelated word island.
  • 〈p〉 in ptarmigan was apparently suggested by Greek words such as pteron ('wing')

• Non-rhotic 〈r〉 accents: 〈r〉 is silent in such words as hard, feathered

• h-dropping accents: 〈h〉 is silent

• silent letters in compound words: compound words are often simplified in pronunciation, while their spelling remains the same. For example, cupboard and breakfast were once pronounced as written, but were then simplified over time.

The Wikipedia section goes more in-depth on the purpose of silent letters and how they originate in words.

Solution 2:

In phonetics, I find three terms used to designate a silent letter (or letters):

1. 'silent letter',

2. 'mute letter',

3. 'zero sound', or simply 'zero'.

Of these, 'silent letter' (1) appears to be most common. The uses, however, might be said to be colloquial, rather than technical and specific to phonetics.

'Mute letter' (2) is also used. The term is attested in use with a special sense for grammar and phonetics, as shown in OED Online:

mute, adj. and n.
....
4. Grammar and Phonetics
....
b. Of a letter: not pronounced, silent.

["mute, adj. and n.3". OED Online. June 2016. Oxford University Press. http://www.oed.com/view/Entry/124309 (accessed July 18, 2016).]

Attestation ranges from 1638-2005. The publications cited are not, however, exclusively devoted to phonetics, but are more general: Barnabæ Itinerarium (1638); Hist. Druids (a1722); Proc. Philol. Soc. (1840); Dict. Mod. Eng. Usage (1926); Understanding French Verse (2005).

This sense of 'mute' is invariably adjectival.

Other—but obsolete, historical and rare—senses of 'mute' used as a noun and adjective in phonetics are given. These obsolete senses do not offer an answer to the question, because even if they were not obsolete, etc., they refer only to 'silent' consonants:

4. Grammar and Phonetics.
†a. Of a consonant: plosive, stopped. Obs.
....
†c. Of a consonant: voiceless. Obs.
....
B. n.³
1. Phonetics. A mute or stopped consonant; a plosive. Now hist. and rare.

(op. cit.)

'Zero sound' (3), also 'zero', however, promises to offer a complete and direct answer to the question. The term and the (absence of) sound it denotes is represented in IPA with ∅.

In an alphabetic writing system, a silent letter is a letter that, in a particular word, does not correspond to any sound in the word's pronunciation. Phonetic transcriptions that better depict pronunciation and which note changes due to grammar and proximity of other words require a symbol to show that the letter is mute. Handwritten notes use a circle with a line through it and the sound is called "zero"....

(Wikipedia, "Silent letter")

While I was at first incredulous (for philosophical reasons, among others), I quickly uncovered support, that is, attestation for the sense, in a wide range of publications specifically dealing with phonetics. I offer a somewhat random selection from those publications:

In accordance with the phonetic laws of the Türkic language the word aluank could have variants Alan, Alban, Alvan. The sound k, apparently, is a part of an affix of belonging -nyky (Aluinnyky - ‘the people belonging to aluan’). Strongly reduced y (like “i“ in “it“) is almost not heard, therefore it dropped out very quickly, double nn in due course gives one n, thus comes a word aluank, where the sound k is further reduced. As to the sound u, it sounds as w, and w usually sounds as a zero sound, or b, or v.

(From Alans - Türkic etymology; bold emphasis mine.)

If the sound that should cover the phonological /r/ slot is not present, tier 2 will simply indicate zero. The symbol adopted in the picture is [Ø].

(From "Diachronic change in the postvocalic /r/ in the Dutch of Amsterdam. Section 9.3.2. Zero sound and special cases", p. 29.)

This group can also yield j and zero sound, but these cases are very easy to explain and therefore will not be dealt with at length in this article.

(From note 1, p. 2, in "An Unknown Law of Elision in Western Romance Languages", Revista Eletrônica de Divulgação Científica em Língua Portuguesa, Lingüística e Literatura - Ano 04 n. 06-1º Semestre de 2007. See also two other instances in this article.)

... mainly to facilitate making the distinction between glottal stop and zero as in [a?e] versus [ae].

(From "Auditory vs. Articulatory Training in Exotic Sounds. Final Report", p 3.)