Editing Fortis and lenis (section)

=== Articulatory strength ===
Later studies have shown that articulatory strength is not completely irrelevant.  The articulators in the mouth can move with a greater velocity<ref>{{Harvcoltxt|Smith|McLean-Muse|1987}}</ref> and/or with higher [[electromyography|electromyographic]] activation levels of the relevant articulatory muscles<ref>{{Harvcoltxt|Slis|1971}}</ref> with fortis consonants than with lenis ones.

==== Oral pressure ====
Generally, voiceless stops have greater oral pressure than voiced ones, which could explain this greater articulatory energy.   In [[Ewe language|Ewe]], for example, the lips reach closure faster in articulating {{IPA|/p/}} than in {{IPA|/b/}}, making the lip closure longer.<ref>{{Harvcoltxt|Ladefoged|Maddieson|1996|p=95}}</ref>  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.<ref>{{Harvcoltxt|Ladefoged|Maddieson|1996|p=96}}</ref> Indeed, a number of languages have been proposed as making strength differences independently of voicing, such as [[Tabasaran language|Tabasaran]], [[Archi language|Archi]], [[Udi language|Udi]], and [[Aghul language|Aghul]].<ref>{{Harvcoltxt|Kodzasov|1977|p=228}}</ref><ref>[http://titus.fkidg1.uni-frankfurt.de/didact/caucasus/nekklaut.htm#XFN10 Consonant Systems of the Northeast Caucasian Languages on TITUS DIDACTICA]</ref>

==== Subglottal pressure ====
It is rare for the use of greater ''respiratory'' energy for [[segment (linguistics)|segments]] to occur in a language, though some examples do exist, such as [[Korean language|Korean]], which makes a three way contrast amongst most of its obstruents with voiceless, [[aspirated consonant|aspirated]], and a third [[faucalized voice]]d set that involves both an increase in subglottal pressure as well as greater glottal constriction and tenseness in the walls of the vocal tract.<ref>{{Harvcoltxt|Ladefoged|Maddieson|1996|p=95}}</ref>  [[Igbo language|Igbo]] has also been observed to utilize an increase in subglottal pressure involving its aspirated consonants.<ref>{{Harvcoltxt|Ladefoged|Maddieson|1996|p=95}}</ref>