collapsed into a single phoneme word-finally. Maddieson and colleagues also confirm that the ejective fricatives in Tlingit are in fact true ejectives, despite the widely-held assumption that ejective fricatives are not actually phonetically ejective but are as a sequence of fricative and glottal stop. In Tlingit, at least, the articulation of ejective fricatives includes complete closure of the glottis before frication begins, and the larynx is raised in the same manner as with ejective stops. Characteristically, the ejective fricatives in Tlingit feature a much smaller aperture for frication than is found in ordinary fricatives. That articulation provides increased resistance to counter the continual loss of dynamic airstream pressure. Also, ejective fricatives appear to include tightening of the pharyngeal muscles, which reduces the diameter of the air column and so further increases pressure. That pharyngeal constriction is not true pharyngealization, however, since the diameter is still greater than what is found in pharyngealized consonants in other languages. Vowels Tlingit has eight vowels, four vowels further distinguished formally by length. However, the length distinction is often in terms of tenseness rather than length, particularly in rapid speech. For the Northern dialect, the dominant spoken dialect of Tlingit and the standard for written Tlingit, every vowel may take either high or low tone; in the orthography high tone is indicated by an acute accent (áa) and low tone is unmarked (aa). The Southern and Transitional dialects have a mid tone which is unmarked and additional low tone which is marked by a grave accent (àa). The Inland Tlingit orthography does not use vowel digraphs. Instead, short high vowels are marked with an acute accent, long high vowels are marked with a circumflex, and long low vowels are marked with a grave accent. Short low vowels are unmarked. Coastal Tlingit <áa> and <aa> are Inland <â> and <à> respectively. Coastal <éi> and <ei> are Inland <ê> and <è>, Coastal <ée> and <ee> are Inland <î> and <ì>, and Coastal <óo> and <oo> are Inland <û> and <ù>. {| class="wikitable" style="text-align: center" |- ! rowspan=2| ! colspan=3| Tense/Long ! colspan=3| Lax/Short |- ! front || central || back ! front || central || back |- ! close | | | | | | |- ! mid | | | | | | |- ! open | | | ( ) | | ( ) | |} As noted in the vowel chart above, there is