Fortis and lenis

In linguistics, fortis and lenis (/ˈfɔːrtɪs ˈlɛ-, ˈlnɪs/; Latin for "strong" and "weak"), sometimes identified with tense and lax, are pronunciations of consonants with relatively greater and lesser energy. English has fortis consonants, such as the p in pat, with a corresponding lenis consonant, such as the b in bat. Fortis and lenis consonants may be distinguished by tenseness or other characteristics, such as voicing, aspiration, glottalization, velarization, length, and length of nearby vowels. Fortis and lenis were coined for languages where the contrast between sounds such as p and b does not involve voicing (vibration of the vocal cords).[1]


Originally, the terms were used to refer to an impressionistic sense of strength differences, though more sophisticated instruments eventually gave the opportunity to search for the acoustic and articulatory signs. For example, Malécot (1968) tested whether articulatory strength could be detected by measuring the force of the contact between the articulators or of the peak pressure in the mouth. Because such studies initially found little to substantiate the terminology, phoneticians have largely ceased using them, though they are still commonly used as "phonological labels for specifying a dichotomy when used language-specifically."[2] This can be useful when the actual articulatory features underlying the distinction are unknown, under-researched or unimportant.


Voice onset time
+ Aspirated
0 Tenuis

Later studies have shown that articulatory strength is not completely irrelevant. The articulators in the mouth can move with a greater velocity[3] and/or with higher electromyographic activation levels of the relevant articulatory muscles[4] with fortis consonants than with lenis ones.

Generally, voiceless stops have greater oral pressure than voiced ones, which could explain this greater articulatory energy. In Ewe, for example, the lips reach closure faster in articulating /p/ than in /b/, making the lip closure longer.[5] These differences in oral articulatory energy in consonants of different laryngeal settings is fairly widespread, though the correlation of energy and voicing is not universal.[6] Indeed, a number of languages have been proposed as making strength differences independently of voicing, such as Tabasaran,[7] Archi,[8] Udi,[9] and Aghul.[10]

"Fortis" and "lenis" have also been used to refer to contrasts of consonant duration in languages like Jawoyn,[11] Ojibwe,[12] Dalabon, Kunwinjku,[13] and Zurich German.[14] The Zapotec languages are also considered to have contrast of length rather than of voicing.[15] For example, in Mixe, lenis consonants are not only pronounced shorter than their fortis counterparts, but they are also prone to voicing in voiced environments, which fortis consonants are not.

This association with longer duration has prompted some to propose a diachronic link between fortis consonants and gemination.[16] Payne (2006) even proposes that gemination is itself a process of fortition in Italian.

In English, use of the terms "fortis" and "lenis" is useful to refer to contrasts between consonants that have different phonetic attributes depending on context. The alveolar consonants /t/ and /d/, for example:

Allophones of American English /t/ and /d/ [17]
lenis fortis
form example form example
Word-initial [d̥] [ˈd̥ɑ̆k̚] dock [tʰ] [ˈtʰɑ̆p̚] top
Syllable-final [ˈnɑd̥] nod [V̆t̚] [ˈnɑ̆t̚] knot
[V̆ˀt̚] [ˈnɑ̆ˀt̚]
[V̆ʔ] [ˈnɑ̆ʔ]
Stressed syllable-initial [d] [əˈdɑ̆pt] adopt [tʰ] [əˈtʰɑ̆p̚] atop
Word-internal unstressed [Vɾ] [ˈɑɾɹ̩][a] odder [ɾ] [ˈɑ̆ɾɹ̩] otter
[V̆ɾ] [ˈɑ̆ɾɹ̩]
Following [s][b] [t] [ˈstɑ̆p̚] stop
^a Depending on dialect, /t/ and /d/ may not neutralize with flapping, with the contrast manifesting itself in the preceding vowel's duration.
^b In the same syllable, the distinction between /t/ and /d/ is lost after [s].

As the above table shows, no one feature is adequate to accurately reflect the contrasts in all contexts. Word-initially, the contrast has more to do with aspiration; /t/ is aspirated and /d/ is an unaspirated voiceless stop. In the syllable coda, however, /t/ is instead pronounced with glottalization, unrelease, and a shorter vowel while /d/ remains voiceless. In this way, the terms fortis and lenis are convenient in discussing English phonology, even if they are phonetically imprecise.

It is rare for the use of greater respiratory energy for segments to occur in a language, though some examples do exist, such as Korean, which makes a three way contrast amongst most of its obstruents with voiceless, aspirated, and a third faucalized voiced set that involves both an increase in subglottal pressure as well as greater glottal constriction and tenseness in the walls of the vocal tract.[18] Igbo has also been observed to utilize an increase in subglottal pressure involving its aspirated consonants.[19]

In southern German dialects, the actual distinction underlying obstruent pairs varies somewhat depending on the dialect, but is often one of length—fortis sounds are pronounced geminated in all positions in a word, even at the end of a word or before other consonants.

Many North Caucasian languages (Northwest and especially Northeast) have a consonantal distinction described as "strong" or "preruptive" that has concomitant length. Akhvakh and other Northeast Caucasian languages even possess a distinction between strong/long and weak/short ejective consonants: [qʼaː] ('soup') vs. [qʼːama] ('cock's comb')

Kodzasov (1977) describes the fortis consonants for Archi:

Strong phonemes are characterized by the intensiveness (tension) of the articulation. The intensity of the pronunciation leads to a natural lengthening of the duration of the sound, and that is why strong [consonants] differ from weak ones by greater length. [However,] the adjoining of two single weak sounds does not produce a strong one […] Thus, the gemination of a sound does not by itself create its tension.[20]

Fortis stops in Australian Aboriginal languages such as Rembarunga (see Ngalakgan) also involve length, with short consonants having weak contact and intermittent voicing, and long consonants having full closure, a more powerful release burst, and no voicing. It is not clear if strength makes the consonants long, or if during long consonants there is a greater opportunity for full articulation.

Articulatory strength can reinforce other distinctions. Ewe, for example, which contrasts a voiceless bilabial fricative /ɸ/ and a voiceless labiodental fricative /f/, pronounces the latter markedly more strongly than /f/ in most languages.[citation needed] This helps differentiate what would otherwise be a very subtle distinction.


The IPA provides no specific means for representation of a fortis–lenis contrast. The extensions to the International Phonetic Alphabet provide a diacritic for strong articulation (e.g. [t͈]) and weak articulation ([t͉]), but this does not cover all of the phonetic differences that have been categorized under fortis and lenis. Americanist phonetic notation uses fortis [t͈] and lenis [t᷂].

Different ways of transcribing the fortis–lenis contrast have been used. For instance, for the transcription of the Zürich German fortis–lenis contrast – which involves neither voicing nor aspiration –, notations such as the following ones have appeared in the relevant literature:[21]

  • The fortis–lenis contrast may be transcribed with plain [p t k f s x …] vs. [b d ɡ v z ɣ …], even though this is in contradiction to their IPA definition that relies solely on voice.
  • The fortis–lenis contrast may be transcribed as a gemination contrast ([pː tː kː fː sː xː …] or [pp tt kk ff ss xx …] vs. [p t k f s x …]).
  • The fortis–lenis contrast may be transcribed as [p t k f s x …] vs. [b̥ d̥ ɡ̊ v̥ z̥ ɣ̊ …], that is, the lenes are marked with the IPA diacritic for voicelessness. By strict IPA definition, ⟨b̥ d̥ ɡ̊ v̥ z̥ ɣ̊ …⟩ in this context can only denote partially devoiced obstruents. This notation emphasizes that there is more than just voice to the contrast between [p t k f s x …] vs. [b̥ d̥ ɡ̊ v̥ z̥ ɣ̊ …].

This means that depending on the system, ⟨p t k f s x …⟩ may have opposite values, i.e. they may represent either fortis or lenis sounds.

See also



  • Blevins, Juliette (2004). Evolutionary phonology. Cambridge: Cambridge University Press.
  • Catford, J.C. (1977). Fundamental problems in phonetics. Bloomington: Indiana University Press.
  • Elugbe, Ben Ohi (1980), "Reconstructing the lenis feature in proto-Ẹdoid", Journal of African Languages and Linguistics, 2: 39–67, doi:10.1515/jall.1980.2.1.39, S2CID 143757407
  • Fleischer, Jürg; Schmid, Stephan (2006), "Zurich German" (PDF), Journal of the International Phonetic Association, 36 (2): 243–253, doi:10.1017/s0025100306002441, archived from the original (PDF) on 2016-03-03, retrieved 2008-12-06
  • Fletcher, Janet; Evans, Nicholas (2002), "An acoustic phonetic analysis of intonational prominence in two Australian languages", Journal of the International Phonetic Association, 32 (2): 123–140, doi:10.1017/s0025100302001019
  • Halle, Morris; Hughes, GW; Radley, JPA (1957), "Acoustic properties of stop consonants", Journal of the Acoustical Society of America, 29: 107–116, doi:10.1121/1.1908634
  • Jaeger, Jeri J. (1983), "The fortis/lenis question: evidence from Zapotec and Jawoñ", Journal of Phonetics, 11 (2): 177–189, doi:10.1016/S0095-4470(19)30814-9
  • Kodzasov, Sandro (1977), "Fonetika Archinskogo Jazyka. Part 2", in Kibrik, A.E.; Kodzasov, S.V.; Olovjannikova, I.P.; et al. (eds.), Opyt Strukturnogo Opisanija Archinskogo Jazyka, 1, Moscow: Izdatel'stvo Moskovskogo Universiteta
  • Kodzasov, Sandro; Muravjeva, I.A. (1982), Missing or empty |title= (help)
  • Kodzasov, Sandro (1990), Missing or empty |title= (help)
  • Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 978-0-631-19815-4.
  • Malécot, André (1968), "The Force of Articulation of American Stops and Fricatives as a Function of Position", Phonetica, 18 (2): 95–102, doi:10.1159/000258603
  • Merrill, Elizabeth (2008), "Tilquiapan Zapotec" (PDF), Journal of the International Phonetic Association, 38 (1): 107–114, doi:10.1017/S0025100308003344
  • Nellis, Donald G.; Hollenbach, Barbara E. (1980), "Fortis versus lenis in Cajonos Zapotec phonology", International Journal of American Linguistics, 46 (2): 92–105, doi:10.1086/465639
  • Payne, Elinor (2006), "Non-durational indices in Italian geminate consonants", Journal of the International Phonetic Association, 36 (1): 83–95, doi:10.1017/s0025100306002398
  • Silverman, Daniel (2004), "On the phonetic and cognitive nature of alveolar stop allophony in American English" (PDF), Cognitive Linguistics, 15 (1): 69–93, doi:10.1515/cogl.2004.002
  • Slis, I.H. (1971), "Articulatory effort and its durational and electromyographic correlates", Phonetica, 23 (3): 171–188, doi:10.1159/000259338
  • Smith, Bruce L.; McLean-Muse, Ann (1987), "Kinematic Characteristics of Postvocalic Labial Stop Consonants Produced by Children and Adults", Phonetica, 44 (4): 227–237, doi:10.1159/000261800, PMID 3505356
  • Swadesh, Morris (1947), "The phonemic structure of Proto-Zapotec", International Journal of American Linguistics, 13 (4): 220–230, doi:10.1086/463959

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