Editing Click consonant (section)

===Variation among languages===
In a comparative study of clicks across various languages, using her own field work as well as phonetic descriptions and data by other field researchers, Miller (2011) posits 21 types of clicks that contrast in manner or airstream.<ref group=note>Not counting the egressive "spurt" in Damin, and three additional voiced manners in Western ǃXoo, which pair up with voiceless manners.</ref> The [[homorganic]] and heterorganic affricated ejective clicks do not contrast in any known language, but are judged dissimilar enough to keep separate. Miller's conclusions differ from those of the primary researcher of a language; see the individual languages for details.
* [[Taa language|Taa]] (ǃXóõ) and [[Nǁng language|Nǁng]] (Nǀuu) are [[Tuu languages]], from the two branches of that family.
* [[ǂʼAmkoe language|ǂʼAmkoe]] (ǂHoan) and [[Juǀʼhoan language|Juǀʼhoan]] (ǃKung) are [[Kxʼa languages]], from the two branches of that family.
* [[Korana language|Korana]] and [[Gǀwi language|Gǀui]] (Gǁana) are [[Khoe languages]], from the two branches of that family.
(all spoken primarily in [[South Africa]], [[Namibia]] and [[Botswana]]; [[Khoekhoe language|Khoekhoe]] is similar to Korana except it has lost ejective {{IPA|/ᵏꞰ͡χʼ/}})
* [[Sandawe language|Sandawe]] and [[Hadza language|Hadza]] are [[language isolate]]s spoken in [[Tanzania]]
* [[Dahalo language|Dahalo]] is a [[Cushitic languages|Cushitic]] language of [[Kenya]]
* [[Xhosa language|Xhosa]] and [[Yeyi language|Yeyi]] are [[Bantu languages]], from the two geographic areas of that family that have acquired clicks.
([[Zulu language|Zulu]] is similar to Xhosa apart from not having {{IPA|/ᵑꞰˀ/}})
* [[Damin]] was an initiation jargon in northern [[Australia]].

Each language below is illustrated with Ʞ as a placeholder for the different click types. Under each language are the orthography (in italics, with old forms in parentheses), the researchers' transcription (in {{angbr|angle brackets}}), or allophonic variation (in [brackets]). Some languages also have labialised<!--not just Dahalo--> or prenasalised clicks in addition to those listed below.

<div style="margin:0 auto;overflow:scroll;width:auto;max-width:100%">
{| class=wikitable
! colspan=3 rowspan=2 | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Language ||  colspan=2| Tuu ||  colspan=2| Kxʼa ||  colspan=2| Khoe || rowspan=2| Sandawe || rowspan=2| Hadza|| Cushitic || colspan=2| Bantu || Australian
|-
! Taa || Nǁng || ǂʼAmkoe || Juǀʼhoan<ref group=note>Ekoka ǃKung has an additional manner, {{IPA|ˀᵑꞰ}}. Grootfontein and Mangetti Dune ǃKung, on the other hand, have a substantially smaller inventory: {{IPA|ᵏꞰ, ᶢꞰ, Ʞʰ, ᵑꞰ, ᵑ̊Ʞʱ, ᵑꞰˀ, Ʞ͡χ, Ʞ͡kxʼ}}.</ref> || Korana || Gǀui || Dahalo || Xhosa || Yeyi || Damin
|-
! colspan=3 | Manner&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
| colspan=3 align=center bgcolor="#f2f2f2" | {{IPA|ʘ, ǂ, ǃ, ǁ, ǀ}} || colspan=3 align=center bgcolor="#f2f2f2" | {{IPA|ǂ, ǃ, ǁ, ǀ}} || colspan=2 align=center bgcolor="#f2f2f2" | {{IPA|ǃ, ǁ, ǀ}} || align=center bgcolor="#f2f2f2" | {{IPA|ǀ}} || align=center bgcolor="#f2f2f2" | {{IPA|ǃ, ǁ, ǀ}} || align=center bgcolor="#f2f2f2" | {{IPA|ǂ, ǃ, ǁ, ǀ}} || align=center bgcolor="#f2f2f2" | {{IPA|ʘ, 𝼊, ǃ, ǀ}}
|-
|rowspan=4|Simple<br />oral<br />click
| ''[[Tenuis consonant|Tenuis]]''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵏꞰ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞ}}*
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[ᵏꞰ]}}
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''Ʞ (c, ç, q, x)''
<!-- Korana -->| bgcolor="#f0c0c0" align=center | ''Ʞg''
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|kꞰ}}
<!-- Sandawe -->| bgcolor="#f0c0c0" align=center | ''c, q, x''
<!-- Hadza -->| bgcolor="#f0c0c0" align=center | ''c, q, x (Ʞ)'' || 
<!-- Xhosa -->| bgcolor="#f0c0c0" align=center | ''c, q, x''
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞ}} ||
|-
| ''Voiced''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰ}}*
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|ᶢꞰ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[ᶢꞰ]}}
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''gꞰ (dq etc.)'' || 
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰ}}
<!-- Sandawe -->| bgcolor="#f0c0c0" align=center | ''gq etc.''<br />{{IPA|[ᶢꞰ}} ~ {{IPA|ŋᶢꞰ]}} ||  ||  || 
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰ}} ||
|-
| ''Aspirated''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵏꞰʰ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞh}}*
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞʰ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[ᵏꞰʰ]}}
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''Ʞh (qh etc.)''
<!-- Korana -->| bgcolor="#f0c0c0" align=center | ''Ʞkh''
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|kꞰh}}
<!-- Sandawe -->| bgcolor="#f0c0c0" align=center | ''qh etc.''
<!-- Hadza -->| bgcolor="#f0c0c0" align=center | ''qh etc. (Ʞh)'' || 
<!-- Xhosa -->| bgcolor="#f0c0c0" align=center | ''qh etc.''
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞh}} (= Ʞx ?) ||
|-
| ''Breathy-voiced''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰʱ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰh}}* ||  || 
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''gꞰh (dqh etc.)''<br />{{IPA|[ᶢꞰʱ ~ ᶢꞰˠ]}} ||  ||  ||  ||  || 
<!-- Xhosa -->| bgcolor="#f0c0c0" align=center | ''gq etc.''{{refn|Perhaps better described as [[slack voice]]. Tone-depressor effect.<ref>Jessen & Roux, 2002. ''[https://web.archive.org/web/20140703113602/http://www.phonetik.uni-muenchen.de/~hoole/kurse/hslarynx/jessenroux_jphon_30_2002.pdf Voice quality differences associated with stops and clicks in Xhosa]''</ref>|group=note}} || ||
|-
|rowspan=4|[[Nasal click consonant|Simple<br />nasal<br />click]]
| ''Voiceless''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵑ̊Ʞ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|nhꞰ}}*<br />{{IPA|[ŋ̊ᵑꞰ]}} ||  ||  ||  ||  ||  ||  ||  ||  ||  || ||
|-
| ''Voiced''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵑꞰ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|nꞰ}}* <br />{{IPA|[ŋ̈ᵑꞰ]}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|ᵑꞰ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[ᵑꞰ]}}
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''nꞰ (nq etc.)''
<!-- Korana -->| bgcolor="#f0c0c0" align=center | ''Ʞn''
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|ŋꞰ}}
<!-- Sandawe -->| bgcolor="#f0c0c0" align=center | ''nq etc.''
<!-- Hadza -->| bgcolor="#f0c0c0" align=center | ''nq etc. (nꞰ)''
<!-- Dahalo -->| bgcolor="#f0c0c0" align=center | {{IPA|/ᵑǀ/}}
<!-- Xhosa -->| bgcolor="#f0c0c0" align=center | ''nq etc.''
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|ŋꞰ}}
<!-- Damin -->| bgcolor="#f0c0c0" align=center | {{angbr|Nǃ}}
|-
| ''(Delayed) aspiration<br />(prenasalised between vowels)''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵑ̊Ʞʰʱ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞhh}}<br />{{IPA|[ŋ̊↓Ʞh]}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|ᵑ̊Ʞʰ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[ᵑ̊Ʞʱ ~ ŋᵑ̊Ʞʱ]}}
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''Ʞʼh (qʼh etc.)''
<!-- Korana -->| bgcolor="#f0c0c0" align=center | ''Ʞh''
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|ŋꞰh}} ||  ||  ||  ||  || ||
|-
| ''Breathy-voiced''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵑꞰʱ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|nꞰhh}} ||  || 
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''nꞰh (nqh etc.)'' ||  ||  ||  ||  || 
<!-- Xhosa -->| bgcolor="#f0c0c0" align=center | ''ngq etc.''<ref group=note>Tone-depressor effect. Sometimes a prenasalized click with a short, voiced oral occlusion, but usually without.</ref> || ||
|-
| colspan=2| ''Preglottalised nasal click''|| bgcolor="#c0c0f0" align=center | {{IPA|/ˀᵑꞰ/}} <!--Not placed under glottalized because the lingual airstream is not glottalized-->
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|ʼnꞰ}}*  || 
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[ʔᵑꞰ]}} || align=center | (in Ekoka) ||  ||  ||  ||  ||  ||  || ||
|-
|rowspan=4|[[Glottalised click|Glottalised<br />click]]
| ''Oral / velar ejective'' || bgcolor="#c0c0f0" align=center | {{IPA|/ᵏꞰʼ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞʼ}}* || || || || |
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|kꞰʼ}} || || || ||
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞʼ}} ||
|-
| ''Creaky-voiced oral'' || bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰʼ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰʼ}}* ||  ||  ||  ||  ||  ||  ||  ||  ||  || ||
|-
| ''Nasal (silent initially,<br />prenasalised after vowels)''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵑ̊Ʞˀ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞʼʼ}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|ᵑ̊Ʞˀ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞˀ ~ ŋˀꞰ]}}
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''Ʞʼ (qʼ etc.)''<br /><small>(w/ nasal vowels)</small>
<!-- Korana -->| bgcolor="#f0c0c0" align=center | ''Ʞ''
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|kꞰʔ}} ({{IPA|ŋ̊Ʞʔ}})
<!-- Sandawe -->| bgcolor="#f0c0c0" align=center | ''qʼ etc.''<br />{{IPA|[Ʞˀʔ}} ~ {{IPA|ŋʔꞰˀ]}}
<!-- Hadza -->| bgcolor="#f0c0c0" align=center | ''qq etc.''<br />''(Ʞʼ ~ nꞰʼ)''
<!-- Dahalo -->| bgcolor="#f0c0c0" align=center | {{IPA|/ᵑǀˀ/}}
<!-- Xhosa -->| bgcolor="#f0c0c0" align=center | ''nkq etc.'' ?<ref>According to Nurse & Philippson (2003:616). This is typically transcribed as a prenasalized click, and is not included in Miller.</ref>
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|ŋꞰʼ}} ||
|-
| ''Nasal (prenasalised initially) ''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵑꞰˀ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|nꞰʼʼ}} ||  ||  ||  ||  ||  ||  ||  ||  ||  || ||
|-
|rowspan=6 bgcolor="#f2f2f2" |[[Pulmonic-contour click consonant|Pulmonic<br />contour]]
| bgcolor="#f2f2f2" |''Tenuis stop''|| bgcolor="#c0c0f0" align=center | {{IPA|/Ʞ͡q/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞq}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞq}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞq]}}
!  || 
<!-- G/ui -->|  bgcolor="#f0c0c0" align=center | {{angbr|qꞰ}}
!  ||  ||  ||  || ||
|-
| bgcolor="#f2f2f2" |''Voiced (and prenasalised)''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰ͡ɢ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰq}}<br />{{IPA|[ᶰꞰɢ ~ Ʞɢ]}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞɢ]}}<ref group=note>not prenasalized</ref>
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | ({{IPA|[ᶰꞰɢ]}})<ref group=note>perhaps borrowed from Gǀui</ref>
!  || 
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|ɢꞰ}}<br />{{IPA|[ᶰꞰɢ]}}
!  ||  ||  ||  || ||
|-
| bgcolor="#f2f2f2" |''Aspirated stop''|| bgcolor="#c0c0f0" align=center | {{IPA|/Ʞ͡qʰ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞqh}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞqʰ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞqʰ]}}
!  || 
<!-- G/ui -->|  bgcolor="#f0c0c0" align=center | {{angbr|qꞰh}}
!  ||  ||  ||  || ||
|-
| bgcolor="#f2f2f2" |''Breathy-voiced ''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰ͡ɢʱ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰqh}}
!  ||  ||  ||  ||  ||  ||  ||  ||  || ||
|-
| bgcolor="#f2f2f2" |''Voiceless fricative ''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᵏꞰ͡χ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞx}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞχ}}
<!-- =Hoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞq͡χ]}}
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''Ʞx (qg etc.)''
!
<!-- G/ui -->|  bgcolor="#f0c0c0" align=center | {{angbr|qꞰχ}}
!  ||  ||  || 
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞx}} (?)
!
|-
| bgcolor="#f2f2f2" |''Voiced fricative (prenasalised) ''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰ͡ʁ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰx}}<br />{{IPA|[ᶢꞰ͡χ ~ ɴᶢꞰ͡ʁ]}}
!  || 
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''gꞰx (dqg etc.)''
!  ||  ||  ||  ||  ||  ||  ||
|-
|rowspan=5 bgcolor="#f2f2f2" |[[Ejective-contour click consonant|Ejective<br />contour]]
| bgcolor="#f2f2f2" |''Ejective stop''|| bgcolor="#c0c0f0" align=center | {{IPA|/Ʞ͡qʼ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞqʼ}}
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞqʼ]}}
<!-- ǂHoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞqʼ]}}
!  || 
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|qꞰʼ}}
!  ||  ||  ||  || ||
|-
| bgcolor="#f2f2f2" |''Voiced ejective stop'' || bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰ͡qʼ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰqʼ}}
!  ||  ||  ||  ||  ||  ||  ||  ||  || ||
|-
| bgcolor="#f2f2f2" |''Ejective fricative''|| bgcolor="#c0c0f0" align=center | {{IPA|/Ʞ͡χʼ/}}
!
<!-- N/uu -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞχʼ}}
<!-- ǂHoan -->| bgcolor="#f0c0c0" align=center | {{IPA|[Ʞq͡χʼ]}}
!
<!-- Korana -->| bgcolor="#f0c0c0" align=center rowspan=2 | ''Ʞkhʼ''
! ||  ||  ||  || 
<!-- Yeyi -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞqʼ}}<!--affricated per Miller-->
!
|-
| bgcolor="#f2f2f2" |''Heterorganic affricate /<br /> epiglottalised''|| bgcolor="#c0c0f0" align=center | {{IPA|/Ʞ͡kxʼ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|Ʞqxʼ}}
!  || 
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''Ʞk (qgʼ etc.)''<br />{{IPA|[Ʞᵸ]}}
<!-- G/ui -->| bgcolor="#f0c0c0" align=center | {{angbr|qꞰχʼ}}
!  ||  ||  ||  ||  ||
|-
| bgcolor="#f2f2f2" |''Voiced heterorganic <br />affricate / epiglottalised''|| bgcolor="#c0c0f0" align=center | {{IPA|/ᶢꞰ͡kxʼ/}}
<!-- !Xoo -->| bgcolor="#f0c0c0" align=center | {{angbr|gꞰqxʼ}}
!  || 
<!-- Ju/hoan -->| bgcolor="#f0c0c0" align=center | ''gꞰk (dqgʼ etc.)''<br />{{IPA|[ᶢꞰˤ]}}
!  ||  ||  ||  ||  ||  ||  ||
|-
| Egressive<ref group=note>Not technically a click, but the only other attested sound with a lingual airstream mechanism.</ref> || ''(Voiceless "spurt"; labial only)'' || bgcolor="#c0c0f0" align=center | {{IPA|/ʘ↑/}}
|  ||  ||  ||  ||  ||  ||  ||  ||  ||  || 
<!-- Damin -->| bgcolor="#f0c0c0" align=center | {{angbr|pʼ}}
|-
! colspan=2 |  || IPA || Taa || Nǁng || ǂʼAmkoe || Juǀʼhoan || Korana || Gǀui || Sandawe || Hadza || Dahalo || Xhosa || Yeyi || Damin
|}
</div>
Yeyi also has prenasalised {{IPA|/ŋᶢꞰ/}}. The original researchers believe that {{IPA|[Ʞʰ]}} and {{IPA|[Ʞχ]}} are allophones.

A DoBeS (2008) study of the Western ǃXoo dialect of Taa found several new manners: creaky voiced (the voiced equivalent of glottalised oral), breathy-voiced nasal, prenasalised glottalised (the voiced equivalent of glottalised) and a (pre)voiced ejective. These extra voiced clicks reflect Western ǃXoo morphology, where many nouns form their plural by voicing their initial consonant. DoBeS analyses most Taa clicks as clusters, leaving nine basic manners (marked with asterisks in the table). This comes close to Miller's distinction between simple and contour clicks, shaded light and medium grey in the table.