Indecs amrywiaeth ieithyddol

Gall yr indecs amrywiaeth ieithyddol (LDI) cyfeirio at naill ai Indecs Amrywiaeth (iaith) Greenberg neu'r Indecs Amrywiaeth Ieithyddol (ILD) cysylltiedig o Terralingua, sy'n mesur newidiadau yn yr LDI sylfaenol dros amser.

Indecs Amrywiaeth Greenberg (LDI) yw'r tebygolrwydd y bydd gan ddau berson a ddewisir o'r boblogaeth ar hap famiaith wahanol; felly mae'n amrywio o 0 (mae gan bawb yr un famiaith) i 1 (nid oes gan unrhyw dau berson yr un famiaith). Mae'r ILD yn mesur sut mae'r LDI wedi newid dros amser; mae ILD byd-eang o 0.8 yn nodi colled amrywiaeth o 20% ers 1970, ond mae cymarebau uwch nag 1 yn bosib, ac wedi ymddangos mewn indecsau rhanbarthol.

Mae cyfrifiant yr indecs amrywiaeth yn seiliedig ar boblogaeth pob iaith fel cyfran o gyfanswm y boblogaeth. Ni all y mynegai roi cyfrif llawn am fywiogrwydd ieithoedd. Hefyd, mae'r gwahaniaeth rhwng iaith a thafodiaith yn gyfnewidiol ac yn aml yn wleidyddol. Mae nifer fawr o ieithoedd yn cael eu hystyried yn dafodieithoedd iaith arall gan rai arbenigwyr ac ieithoedd ar wahân gan eraill. Nid yw'r indecsau yn ystyried pa mor wahanol yw'r ieithoedd i'w gilydd, ac nid yw'n cofnodi defnydd ail iaith; mae'n ystyried dim ond cyfanswm yr ieithoedd gwahanol, a'u hamlder cymharol fel mamiaith.

 Safleoedd yn ôl gwlad 
SIL International (2017)Data published in Ethnologue: Languages of the World, Twentieth Edition. Summary by Country | Ethnologue, SIL International. Accessed on 13 October 2017.UNESCO (2009)UNESCO World Report – Investing in Cultural Diversity and Intercultural Dialogue{| class="wikitable sortable" style="margin-left:auto;margin-right:auto;text-align: left"RhengGwladLDI10.98820.97430.97340.96850.95960.94870.93380.93390.929100.929110.927120.926130.917140.914150.905160.900170.890180.873190.871200.871210.862220.859230.858240.846250.842260.841270.830280.827290.825300.821310.819320.816330.816340.790350.789360.779370.778380.776390.761400.761410.755420.752430.752440.751450.750460.748470.748480.736490.735500.721510.721520.719530.719540.70955Caribî yr Iseldiroedd0.707560.707570.700580.698590.697600.694610.692620.689630.683640.679650.672660.671670.658680.652690.638700.632710.630720.622730.605740.603750.599760.597770.581780.571790.570800.565810.551820.550830.550840.549850.548860.538870.526880.522890.521900.518910.515920.514930.514940.512950.511960.509970.504980.503990.5001000.5001010.4981020.4951030.4891040.4891050.4871060.4751070.4731080.4701090.4661100.4631110.4611120.4601130.4591140.4571150.4571160.4521170.4461180.4441190.4381200.4291210.4271220.4111230.4051240.4041250.3971260.3891270.3631280.3601290.3501300.3451310.3391320.3361330.3331340.3251350.3181360.3131370.3071380.3031390.2911400.2871410.2851420.2841430.2831440.2761450.2761460.2741470.2671480.2551490.2531500.2521510.2471520.2441530.2441540.2341550.2321560.2281570.2261580.2261590.2241600.2161610.2151620.2101630.2091640.2051650.2021660.1981670.1961680.1921690.1821700.1791710.1741720.1721730.1671740.1651750.1541760.1531770.1461780.1411790.1361800.1231810.1221820.1181830.1161840.1111850.1101860.1061870.1021880.1011890.0991900.0921910.0911920.0891930.0891940.0831950.0761960.0721970.0671980.0661990.0642000.0602010.0532020.0522030.0502040.0502050.0432060.0402070.0402080.0392090.0362100.0362110.0352120.0332130.0292140.0202150.0202160.0192170.0192180.0172190.0122200.0102210.0102220.0072230.0072240.0072250.0032260.0012270.0002280.0002290.0002300.0002310.0002320.000
|
{| class="wikitable sortable" style="margin-left:auto;margin-right:auto;text-align: left"
!Rheng
!Gwlad
!LDI
|-
|1
|
|.990
|-
|2
|
|.972
|-
|3
|
|.965
|-
|4
|
|.965
|-
|5
|
|.960
|-
|6
|
|.950
|-
|7
|
|.948
|-
|8
|
|.942
|-
|9
|
|.930
|-
|10
|
|.929
|-
|11
|
|.928
|-
|12
|
|.919
|-
|13
|
|.917
|-
|14
|
|.912
|-
|15
|
|.901
|-
|16
|
|.901
|-
|17
|
|.897
|-
|18
|
|.897
|-
|19
|
|.876
|-
|20
|
|.870
|-
|21
|
|.869
|-
|22
|
|.855
|-
|23
|
|.853
|-
|24
|
|.849
|-
|25
|
|.846
|-
|26
|
|.846
|-
|27
|
|.843
|-
|28
|
|.820
|-
|29
|
|.817
|-
|30
|
|.808
|-
|31
|
|.805
|-
|32
|
|.797
|-
|33
|
|.792
|-
|34
|
|.788
|-
|35
|
|.785
|-
|36
|
|.777
|-
|37
|
|.773
|-
|38
|
|.772
|-
|39
|
|.762
|-
|40
|
|.758
|-
|41
|
|.753
|-
|42
|
|.749
|-
|43
|
|.748
|-
|44
|
|.748
|-
|45
|
|.748
|-
|46
|
|.742
|-
|47
|
|.734
|-
|48
|
|.732
|-
|49
|
|.701
|-
|50
|
|.696
|-
|51
|
|.693
|-
|52
|
|.693
|-
|53
|
|.691
|-
|54
|
|.680
|-
|55
|
|.678
|-
|56
|
|.670
|-
|57
|
|.666
|-
|58
|
|.665
|-
|59
|
|.663
|-
|60
|
|.657
|-
|61
|
|.656
|-
|62
|
|.646
|-
|63
|
|.641
|-
|64
|
|.609
|-
|65
|
|.608
|-
|66
|
|.607
|-
|67
|
|.596
|-
|68
|
|.595
|-
|69
|
|.593
|-
|70
|
|.592
|-
|71
|
|.589
|-
|72
|
|.587
|-
|73
|
|.579
|-
|74
|
|.576
|-
|75
|
|.574
|-
|76
|
|.566
|-
|77
|
|.556
|-
|78
|
|.551
|-
|79
|
|.549
|-
|80
|
|.547
|-
|81
|
|.547
|-
|82
|
|.540
|-
|83
|
|.526
|-
|84
|
|.521
|-
|85
|
|.521
|-
|86
|
|.519
|-
|87
|
|.509
|-
|88
|
|.503
|-
|89
|
|.498
|-
|90
|
|.498
|-
|91
|
|.494
|-
|92
|
|.492
|-
|93
|
|.491
|-
|94
|
|.484
|-
|95
|
|.482
|-
|96
|
|.476
|-
|97
|
|.466
|-
|98
|
|.456
|-
|99
|
|.453
|-
|100
|
|.444
|-
|101
|
|.438
|-
|102
|
|.428
|-
|103
|
|.416
|-
|104
|
|.397
|-
|105
|
|.389
|-
|106
|
|.389
|-
|107
|
|.387
|-
|108
|
|.386
|-
|109
|
|.386
|-
|110
|
|.379
|-
|111
|
|.376
|-
|112
|
|.373
|-
|113
|
|.366
|-
|114
|
|.362
|-
|115
|
|.359
|-
|116
|
|.353
|-
|117
|
|.347
|-
|118
|
|.339
|-
|119
|
|.332
|-
|120
|
|.331
|-
|121
|
|.324
|-
|122
|
|.313
|-
|123
|
|.313
|-
|124
|
|.313
|-
|125
|
|.307
|-
|126
|
|.289
|-
|127
|
|.283
|-
|128
|
|.272
|-
|129
|Caribî yr Iseldiroedd
|.266
|-
|130
|
|.264
|-
|131
|
|.260
|-
|132
|
|.257
|-
|133
|
|.234
|-
|134
|
|.228
|-
|135
|
|.224
|-
|136
|
|.223
|-
|137
|
|.213
|-
|138
|
|.208
|-
|139
|
|.189
|-
|140
|
|.179
|-
|141
|
|.175
|-
|142
|
|.174
|-
|143
|
|.174
|-
|144
|
|.172
|-
|145
|
|.168
|-
|146
|
|.167
|-
|147
|
|.167
|-
|148
|
|.161
|-
|149
|
|.158
|-
|150
|
|.157
|-
|151
|
|.145
|-
|152
|
|.140
|-
|153
|
|.140
|-
|154
|
|.139
|-
|155
|
|.139
|-
|156
|
|.135
|-
|157
|
|.128
|-
|158
|
|.126
|-
|159
|
|.102
|-
|160
|
|.092
|-
|161
|
|.091
|-
|162
|
|.087
|-
|163
|
|.081
|-
|164
|
|.078
|-
|165
|
|.077
|-
|166
|
|.071
|-
|167
|
|.070
|-
|168
|
|.069
|-
|169
|
|.067
|-
|170
|
|.064
|-
|171
|
|.060
|-
|172
|
|.057
|-
|173
|
|.056
|-
|174
|
|.054
|-
|175
|
|.053
|-
|176
|
|.051
|-
|177
|
|.050
|-
|178
|
|.034
|-
|179
|
|.033
|-
|180
|
|.032
|-
|181
|
|.030
|-
|182
|
|.028
|-
|183
|
|.027
|-
|184
|
|.026
|-
|185
|
|.026
|-
|186
|
|.022
|-
|187
|
|.020
|-
|188
|
|.019
|-
|189
|
|.016
|-
|190
|
|.014
|-
|191
|
|.012
|-
|192
|
|.011
|-
|193
|
|.010
|-
|194
|
|.010
|-
|195
|
|.009
|-
|196
|
|.004
|-
|197
|
|.004
|-
|198
|
|.004
|-
|199
|
|.003
|-
|200
|
|.002
|-
|201
|
|.001
|-
|202
|
|.000
|-
|203
|
|dim
|-
|204
|
|dim
|-
|205
|
|dim
|-
|206
|
|dim
|-
|207
|
|dim
|-
|208
|
|dim
|-
|209
|
|dim
|-
|}
|}

Cyfeiriadau

Categori:Daearyddiaeth ieithyddol
Categori:Ieithyddiaeth gymhwysol
Categori:Mynegrifau