the walls of the vocal tract. Igbo has also been observed to utilize an increase in subglottal pressure involving its aspirated consonants. Consonant length "Fortis" and "lenis" have also been used to refer to contrasts of consonant duration in languages like Jawoyn, Ojibwe, Dalabon, Kunwinjku, and Zurich German. The Zapotec languages are also considered to have contrast of length rather than of voicing. 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. even proposes that gemination is itself a process of fortition in Italian. 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: ('soup') vs. ('cock's comb') Relationship between strength and length describes the fortis consonants for Archi: 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. Enforcement of phonemic distinctions Articulatory strength can reinforce other distinctions. Ewe, for example, which contrasts a voiceless bilabial fricative and a voiceless labiodental fricative , pronounces the latter markedly more strongly than in most languages. This helps differentiate what would otherwise be a very subtle distinction. 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 and , for example: Depending on dialect, and may not neutralize with flapping, with the contrast manifesting itself in the preceding vowel's duration. In the same syllable, the distinction between and is lost after . 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; is aspirated and is an unaspirated voiceless stop. In the syllable coda, however, is instead pronounced with glottalization, unrelease, and a shorter vowel while remains voiceless. In this way,