wikilangs/lo

Lao - Wikilangs Models

Comprehensive Research Report & Full Ablation Study

This repository contains NLP models trained and evaluated by Wikilangs, specifically on Lao Wikipedia data. We analyze tokenizers, n-gram models, Markov chains, vocabulary statistics, and word embeddings.

📋 Repository Contents

Models & Assets

• Tokenizers (8k, 16k, 32k, 64k)
• N-gram models (2, 3, 4, 5-gram)
• Markov chains (context of 1, 2, 3, 4 and 5)
• Subword N-gram and Markov chains
• Embeddings in various sizes and dimensions (aligned and unaligned)
• Language Vocabulary
• Language Statistics

Analysis and Evaluation

• 1. Tokenizer Evaluation
• 2. N-gram Model Evaluation
• 3. Markov Chain Evaluation
• 4. Vocabulary Analysis
• 5. Word Embeddings Evaluation
• 6. Morphological Analysis (Experimental)
• 7. Summary & Recommendations
• Metrics Glossary
• Visualizations Index

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1. Tokenizer Evaluation

Results

Vocab Size	Compression	Avg Token Len	UNK Rate	Total Tokens
8k	3.254x	3.29	0.1618%	425,150
16k	3.649x	3.69	0.1814%	379,183
32k	4.002x	4.05	0.1990%	345,735
64k	4.276x 🏆	4.32	0.2126%	323,587

Tokenization Examples

Below are sample sentences tokenized with each vocabulary size:

Sample 1: .gf ແມ່ນໂດເມນອິນເຕີເນັດລະດັບສູງສຸດຕາມລະຫັດປະເທດ (ccTLD) ສໍາລັບປະເທດເຟນົເກີຍ

Vocab	Tokens	Count
8k	▁. g f ▁ແມ່ນ ໂດເມນອິນເຕີເນັດ ລະດັບສູງສຸດ ຕາມລະຫັດປະເທດ ▁( cctld ) ... (+6 more)	16
16k	▁. g f ▁ແມ່ນ ໂດເມນອິນເຕີເນັດ ລະດັບສູງສຸດ ຕາມລະຫັດປະເທດ ▁( cctld ) ... (+6 more)	16
32k	▁. g f ▁ແມ່ນ ໂດເມນອິນເຕີເນັດ ລະດັບສູງສຸດ ຕາມລະຫັດປະເທດ ▁( cctld ) ... (+5 more)	15
64k	▁. gf ▁ແມ່ນ ໂດເມນອິນເຕີເນັດ ລະດັບສູງສຸດ ຕາມລະຫັດປະເທດ ▁( cctld ) ▁ສໍາລັບປະເທດ ... (+2 more)	12

Sample 2: 6 ສິງຫາ ເປນວັນທີ່ 218 ຊອງປີຕາມປະຕິທິນສຸລິຍະຄະຕິ ເຫດການສຳຄັນ ວັນເກີດ ວັນເສຍຊີວິດ

Vocab	Tokens	Count
8k	▁ 6 ▁ສິງຫາ ▁ເປນວັນທີ່ ▁ 2 1 8 ▁ຊອງປີຕາມປະຕິທິນ ສຸລິຍະຄະຕິ ... (+3 more)	13
16k	▁ 6 ▁ສິງຫາ ▁ເປນວັນທີ່ ▁ 2 1 8 ▁ຊອງປີຕາມປະຕິທິນ ສຸລິຍະຄະຕິ ... (+3 more)	13
32k	▁ 6 ▁ສິງຫາ ▁ເປນວັນທີ່ ▁ 2 1 8 ▁ຊອງປີຕາມປະຕິທິນ ສຸລິຍະຄະຕິ ... (+3 more)	13
64k	▁ 6 ▁ສິງຫາ ▁ເປນວັນທີ່ ▁ 2 1 8 ▁ຊອງປີຕາມປະຕິທິນ ສຸລິຍະຄະຕິ ... (+3 more)	13

Sample 3: ສຸດທິດາ ອະນຸສິນ (ຊື່ຫຼິ້ນ:ມິມີ່) ເປັນນາງງາມ,ນາງແບບຊາວລາວ ແລະເປັນຕົວແທນຈາກແຂວງສະຫ...

Vocab	Tokens	Count
8k	▁ສຸດ ທິດາ ▁ອະນຸ ສິນ ▁( ຊື່ຫຼິ້ນ : ມິ ມີ ່ ... (+18 more)	28
16k	▁ສຸດ ທິດາ ▁ອະນຸ ສິນ ▁( ຊື່ຫຼິ້ນ : ມິ ມີ່ ) ... (+14 more)	24
32k	▁ສຸດທິດາ ▁ອະນຸສິນ ▁( ຊື່ຫຼິ້ນ : ມິ ມີ່ ) ▁ເປັນນາງງາມ , ... (+12 more)	22
64k	▁ສຸດທິດາ ▁ອະນຸສິນ ▁( ຊື່ຫຼິ້ນ : ມິ ມີ່ ) ▁ເປັນນາງງາມ , ... (+10 more)	20

Key Findings

• Best Compression: 64k achieves 4.276x compression
• Lowest UNK Rate: 8k with 0.1618% unknown tokens
• Trade-off: Larger vocabularies improve compression but increase model size
• Recommendation: 32k vocabulary provides optimal balance for production use

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2. N-gram Model Evaluation

Results

N-gram	Variant	Perplexity	Entropy	Unique N-grams	Top-100 Coverage	Top-1000 Coverage
2-gram	Word	3,552	11.79	7,139	20.1%	49.9%
2-gram	Subword	2,184 🏆	11.09	20,562	30.0%	71.8%
3-gram	Word	5,061	12.31	8,179	15.3%	43.3%
3-gram	Subword	18,283	14.16	110,536	10.7%	33.7%
4-gram	Word	15,243	13.90	20,416	8.0%	22.3%
4-gram	Subword	79,610	16.28	344,446	5.8%	18.2%
5-gram	Word	12,635	13.63	15,847	8.0%	21.2%
5-gram	Subword	160,221	17.29	489,758	3.6%	12.7%

Top 5 N-grams by Size

2-grams (Word):

Rank	N-gram	Count
1	ຄ ສ	3,689
2	พ ศ	1,013
3	ພ ສ	932
4	of the	838
5	ປະ ເທດ	375

3-grams (Word):

Rank	N-gram	Count
1	ສ ຄ ສ	245
2	ສາ ທາ ລະ	193
3	ທາ ລະ ນະ	186
4	ພ ສ ຄ	185
5	ຊອງປີຕາມປະຕິທິນສຸລິຍະຄະຕິ ເຫດການສຳຄັນ ວັນເກີດ	169

4-grams (Word):

Rank	N-gram	Count
1	ພ ສ ຄ ສ	185
2	ສາ ທາ ລະ ນະ	183
3	ທາ ລະ ນະ ລັດ	164
4	ຊອງປີຕາມປະຕິທິນສຸລິຍະຄະຕິ ເຫດການສຳຄັນ ວັນເກີດ ວັນເສຍຊີວິດ	164
5	ສະບັບຄົ້ນຄວ້າ ສົມມະນາ ການພິມ ສປປ	139

5-grams (Word):

Rank	N-gram	Count
1	ສາ ທາ ລະ ນະ ລັດ	163
2	ສະບັບຄົ້ນຄວ້າ ສົມມະນາ ການພິມ ສປປ ລາວ	139
3	ສ ສະບັບຄົ້ນຄວ້າ ສົມມະນາ ການພິມ ສປປ	139
4	ຄ ສ ສະບັບຄົ້ນຄວ້າ ສົມມະນາ ການພິມ	139
5	ພ ສ ຄ ສ ສະບັບຄົ້ນຄວ້າ	139

2-grams (Subword):

Rank	N-gram	Count
1	າ ນ	59,706
2	ອ ງ	44,102
3	ນ _	39,271
4	ກ າ	37,742
5	ລ ະ	34,362

3-grams (Subword):

Rank	N-gram	Count
1	ກ າ ນ	28,652
2	ແ ລ ະ	21,130
3	ຂ ອ ງ	19,934
4	ເ ປັ ນ	16,912
5	_ ແ ລ	15,559

4-grams (Subword):

Rank	N-gram	Count
1	_ ແ ລ ະ	15,503
2	ແ ລ ະ _	10,398
3	ຄ ວ າ ມ	6,185
4	ະ ເ ທ ດ	5,750
5	ປ ະ ເ ທ	5,748

5-grams (Subword):

Rank	N-gram	Count
1	_ ແ ລ ະ _	9,660
2	ປ ະ ເ ທ ດ	5,720
3	_ t h e _	3,835
4	ຄ . ສ . _	3,241
5	_ ຄ . ສ .	2,982

Key Findings

• Best Perplexity: 2-gram (subword) with 2,184
• Entropy Trend: Decreases with larger n-grams (more predictable)
• Coverage: Top-1000 patterns cover ~13% of corpus
• Recommendation: 4-gram or 5-gram for best predictive performance

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3. Markov Chain Evaluation

Results

Context	Variant	Avg Entropy	Perplexity	Branching Factor	Unique Contexts	Predictability
1	Word	0.3040	1.235	2.14	178,626	69.6%
1	Subword	1.0554	2.078	12.72	4,475	0.0%
2	Word	0.1004	1.072	1.19	378,257	90.0%
2	Subword	0.7301	1.659	5.16	56,905	27.0%
3	Word	0.0354	1.025	1.06	447,523	96.5%
3	Subword	0.5034	1.418	2.77	293,770	49.7%
4	Word	0.0171 🏆	1.012	1.02	468,823	98.3%
4	Subword	0.3413	1.267	1.85	811,856	65.9%

Generated Text Samples (Word-based)

Below are text samples generated from each word-based Markov chain model:

Context Size 1:

1. ແລະ ຄວາມຊົ່ວ ຫລື ໃນຊາຕເທົ່ານັ້ນບໍ່ແມ່ນເອົາສຫວັນເມື່ອຕາຍແລ້ວ ແລະ ລາງ ເຊັ່ນດຽວກັນກັບຫ້ອງໂຖງສະຖານີທີ່ສາ...
2. ສ ເຖິງ 12 07 ມັງກອນ ເປັນ ລູກ ດ້ວຍ ເຖົ້າ ພໍກະ ເທີນ ເຖົ້າ ກະ ສານ ຂອງ ກະຊວງກະສິກຳແລະປ່າໄມ້
3. the summation takes ເພື່ອປ້ອງກັນບໍ່ໃຫ້ສະ ກຸນເງິນເອີໂຣ ລົ້ມສະຫລາຍ ໃນປີ ນະຄອນ ທີ່ມີຕັ້ງແຕ່ປະມານສະຕະວັດ...

Context Size 2:

1. ຄ ສ ເມຖຸນາ ຄ ສ ຫາ ໂດຍມີກຸງສີອະຍຸດທະຍາເປັນນະຄອນຫຼວງ ອານາຈັກອະຍຸດທະຍານັບວ່າຈະເລີນຮຸ່ງເຮືອງຮັ່ງມີທີ່ສຸດ...
2. พ ศ ราชกิจจานุเบกษา สืบค้นวันที่ 25 มิถุนายน ຕໍ່ມາວັນທີ 17 ພະຈິກ ທີ່ເມືອງກາມາວ ແຂວງກາມາວ ການສຶກສາ ຈົ...
3. of the 20th century fox ອ້າງອີງ ລິ້ງຄ໌ພາຍນອກ sukhoi su 27 ທີ່ສຸດ ມັກຈະ ມີແມງວັນ ຄະ ດີກວ່າ ອາກາດ ແຕ່

Context Size 3:

1. ສ ຄ ສ ສະບັບຄົ້ນຄວ້າ ສົມມະນາ ການພິມ ສປປ ລາວ ເປັນລະດູອັນມີອາກາດໜາວທີ່ສຸດໃນປີ ລະດູໜາວໃນເຂດອົບອຸ່ນແລະເຂດ...
2. ສາ ທາ ລະ ນະ ລັດ ເຢ ເມນ 45 ໝູ່ເກາະເຄ ແມນ 46 ການາດາ 47 ສາ ທາ ລະ ນະ ຂອງ
3. ທາ ລະ ນະ ລັດ ປະ ຊາ ຊົນ ຈີນ 48 ຈີນ ໄທ ເປ ໄຕ້ ຫວັນ 49 ອາ ນາ ເຂດ

Context Size 4:

1. ສາ ທາ ລະ ນະ ລັດ ປະ ຊາ ທິ ປະ ໄຕ ແລະ ການ ປົກ ຄອງ ໂດຍ ກົງ ຂອງ ມົງ ກຸດ
2. ພ ສ ຄ ສ ຕະຫຼອດໄລຍະເວລາທີລາຍການລະເບີດເຖິດເທິງອອກອາກາດຈົນຮອດປະຈຸບັນ ຊ່ວງຊິດຄອມລະເບີດເຖິດເທິງໃນຍຸກຕໍ່ໆມ...
3. ທາ ລະ ນະ ລັດ ບູ ຣຸນ ດີ 97 ສາ ທາ ລະ ນະ ຂອງ ອັ ຟ ກາ ນິ ສ ຖານ

Generated Text Samples (Subword-based)

Below are text samples generated from each subword-based Markov chain model:

Context Size 1:

1. _vens_ໄຊາ​ປະຊ_sh
2. ານ_ຂ້ອຍ​ສ້າມວົງກາວລ
3. ນ​ກລັດທຶນ​ອົງປີ_ລະວົງ

Context Size 2:

1. ານງ​ໂດຍໄປນີ້_ເພື່ອເຈຍ
2. ອງຢ້ຽມເຕະແຂວງ_3100
3. ນ_ໆ_ເປັນເມືອງຍ່ອຍຮັບປ

Context Size 3:

1. ການເລື່ອງທີ່ມີຊີວິດແຕ່ພາເວ
2. ແລະ_ກຸງຣາຊະຖາບັນເທົາ_
3. ຂອງກ້ອນມົກກະພັດຍີ່ປຸ່ນຈະຕຸ

Context Size 4:

1. _ແລະ_ຕຸ໊ກກີ້_ຊິງຮ້ອຍຊິງລ້ານ
2. ແລະ_ປັບປຸງເພື່ອພະສົບແລ້ວ,
3. ຄວາມຮັກສາພະອົງເຈົ້າພະຍາ

Key Findings

• Best Predictability: Context-4 (word) with 98.3% predictability
• Branching Factor: Decreases with context size (more deterministic)
• Memory Trade-off: Larger contexts require more storage (811,856 contexts)
• Recommendation: Context-3 or Context-4 for text generation

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4. Vocabulary Analysis

Statistics

Metric	Value
Vocabulary Size	36,378
Total Tokens	382,077
Mean Frequency	10.50
Median Frequency	3
Frequency Std Dev	92.90

Most Common Words

Rank	Word	Frequency
1	ແລະ	10,966
2	ສ	5,253
3	the	4,001
4	ຄ	3,718
5	1	3,286
6	of	3,039
7	ຂອງ	2,967
8	ໃນ	2,847
9	2	2,607
10	ການ	2,393

Least Common Words (from vocabulary)

Rank	Word	Frequency
1	ປະຕິເສດຄວາມຮັບຜິດຊອບແລະຖືກຕໍາຫຼວດຈັບຕົວເພື່ອສອບຖາມໃນວັນທີ	2
2	ຜູ້ເຄາະຮ້າຍ	2
3	ຢ່າງນ້ອຍ	2
4	ຍ້ອນການສົງໄສວ່າ	2
5	ດື່ມເຄື່ອງດື່ມທີ່ມີສານ	2
6	ແລະອີກ	2
7	ເຈັບປ່ວຍຈາກການບໍລິໂພກເຫຼົ້າປົນເປື້ອນນັ້ນ	2
8	ໂຣມາຍາ	2
9	ເຈເຣັດ	2
10	ລະດູຮ້ອນໃນເມືອງແມ່ນຮ້ອນແລະຊຸ່ມຊື່ນ	2

Zipf's Law Analysis

Metric	Value
Zipf Coefficient	0.9640
R² (Goodness of Fit)	0.996857
Adherence Quality	excellent

Coverage Analysis

Top N Words	Coverage
Top 100	28.8%
Top 1,000	54.5%
Top 5,000	74.0%
Top 10,000	82.5%

Key Findings

• Zipf Compliance: R²=0.9969 indicates excellent adherence to Zipf's law
• High Frequency Dominance: Top 100 words cover 28.8% of corpus
• Long Tail: 26,378 words needed for remaining 17.5% coverage

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5. Word Embeddings Evaluation

5.1 Cross-Lingual Alignment

5.2 Model Comparison

Model	Dimension	Isotropy	Semantic Density	Alignment R@1	Alignment R@10
mono_32d	32	0.7907 🏆	0.3413	N/A	N/A
mono_64d	64	0.4812	0.3220	N/A	N/A
mono_128d	128	0.1381	0.3128	N/A	N/A
aligned_32d	32	0.7907	0.3454	0.0400	0.2780
aligned_64d	64	0.4812	0.3164	0.0760	0.3560
aligned_128d	128	0.1381	0.3154	0.1140	0.4340

Key Findings

• Best Isotropy: mono_32d with 0.7907 (more uniform distribution)
• Semantic Density: Average pairwise similarity of 0.3256. Lower values indicate better semantic separation.
• Alignment Quality: Aligned models achieve up to 11.4% R@1 in cross-lingual retrieval.
• Recommendation: 128d aligned for best cross-lingual performance

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6. Morphological Analysis (Experimental)

This section presents an automated morphological analysis derived from the statistical divergence between word-level and subword-level models. By analyzing where subword predictability spikes and where word-level coverage fails, we can infer linguistic structures without supervised data.

6.1 Productivity & Complexity

Metric	Value	Interpretation	Recommendation
Productivity Index	5.000	High morphological productivity	Reliable analysis
Idiomaticity Gap	0.675	High formulaic/idiomatic content	-

6.2 Affix Inventory (Productive Units)

These are the most productive prefixes and suffixes identified by sampling the vocabulary for global substitutability patterns. A unit is considered an affix if stripping it leaves a valid stem that appears in other contexts.

Productive Prefixes

Prefix	Examples
-ເ	ເມືອງນາກາຍ, ເສ, ເບສດີໄຊເນີ
-ສ	ສິງເສນ, ສະຖານີສາມຢ່ານ, ສົມເດັດພະສີພັດຊະລິນທາບໍລົມລາຊິນີນາດ
-s	skants, stage, scandinavia
-ອ	ອິງຟ້າ, ອະນຸສາວະລີ, ອະດຸນຍະສັກອັກຄະນະເຣດສະຣາທິບໍດີ
-a	ashgabat, at, alison
-ການ	ການສຸ່ມກາຊາ, ການທີ່ຊາວບ້ານຍັງເຊື່ອຖືສິ່ງດັ່ງກ່າວແມ່ນບໍ່ໄດ້ຖື, ການປະຕິວັດເດືອນຕຸລາ
-ກ	ກຽດຕິຍົດຄົນທີວີ, ການສຸ່ມກາຊາ, ການທີ່ຊາວບ້ານຍັງເຊື່ອຖືສິ່ງດັ່ງກ່າວແມ່ນບໍ່ໄດ້ຖື
-m	men, martini, mans

Productive Suffixes

Suffix	Examples
-ນ	ສິງເສນ, ປະຍູນພັນ, ໄລຍະທາງປະມານ
-ງ	ນະຄອນຫລວງ, ຕະວັນພົງ, ພຽງແມ່ນ້ຳຂອງ
-ດ	ຕົ້ນກຳເນີດ, ບ້ານຄຳສະຫວາດ, ແຄ່ຄົນໂທຜິດ
-າ	ແຄນນາດາ, ອິງຟ້າ, ດາ
-s	skants, mans, holdings
-ານ	ໄລຍະທາງປະມານ, ເຄີດິສຖານ, ສະຖານີສາມຢ່ານ
-ກ	ຄາລສະເບີກ, ນຄນປລັນໂລກ, ລັອກ
-e	treble, stage, unicode

6.3 Bound Stems (Lexical Roots)

Bound stems are high-frequency subword units that are semantically cohesive but rarely appear as standalone words. These often correspond to the 'core' of a word that requires inflection or derivation to be valid.

Stem	Cohesion	Substitutability	Examples
tion	2.20x	21 contexts	nation, notion, motion
atio	2.22x	15 contexts	ratio, nation, nations
ະເທດ	1.87x	12 contexts	ຮະເທດ, ປະເທດ, ປີປະເທດ
ະການ	1.71x	13 contexts	ມະການ, ປະການ, ແລະການ
ປະເທ	1.78x	10 contexts	ປະເທດ, ປີປະເທດ, ປະເທດໄທ
ນການ	1.94x	8 contexts	ໃນການ, ບວນການ, ແຜນການ
ປະກອ	1.65x	12 contexts	ປະກອບ, ປະກອນ, ຄຳປະກອບ
ານປະ	1.99x	7 contexts	ການປະກອບ, ການປະສູດ, ການປະກັນ
ສະຖາ	2.02x	6 contexts	ສະຖານ, ສະຖານະ, ສະຖານີ
ງປະເ	2.17x	5 contexts	ຂອງປະເທດ, ແດງປະເສີດ, ແຂວງປະເວດ
ງຈາກ	1.83x	7 contexts	ຮອງຈາກ, ບາງຈາກ, ຫຼັງຈາກ
ທະຍາ	2.05x	5 contexts	ວິທະຍາ, ພັດທະຍາ, ວິທະຍາໄລ

6.4 Affix Compatibility (Co-occurrence)

This table shows which prefixes and suffixes most frequently co-occur on the same stems, revealing the 'stacking' rules of the language's morphology.

Prefix	Suffix	Frequency	Examples
-ເ	-ນ	97 words	ເມືອງຕຸ້ມລານ, ເພື່ອຄັດຄ້ານ
-ສ	-ນ	72 words	ສັດຈະກຸນ, ສ້າງອາຄານຮຽນ
-ເ	-ງ	67 words	ເພາະຫຍັງ, ເຂດສັມພັນທະວົງ
-ສ	-ດ	55 words	ສີດ, ສູນພັດທະນາຊົນນະບົດ
-ແ	-ນ	52 words	ແກນ, ແຂວງສາລະວັນ
-ອ	-ນ	48 words	ອຶນ, ອັສຈັນ
-ເ	-ດ	47 words	ເມືອງຊົນນະບົດ, ເຟສບຸກແຟນເຜດ
-ແ	-ງ	45 words	ແບັງ, ແມ່ນນັກການເມືອງ
-ກ	-ນ	41 words	ກຽກກີດສະຖານ, ກິດຕິກອນຈະເລີນ
-ເ	-າ	39 words	ເມືອງໄຊເຊດຖາ, ເຈົ້າເກດສະດາ

6.5 Recursive Morpheme Segmentation

Using Recursive Hierarchical Substitutability, we decompose complex words into their constituent morphemes. This approach handles nested affixes (e.g., prefix-prefix-root-suffix).

Word	Suggested Split	Confidence	Stem
ວັດສີພຸດທະບາດ	ວັດສີພຸດທະ-ບ-າດ	7.5	ບ
detectors	detector-s	4.5	detector
ການສືບສວນ	ການ-ສືບສວນ	4.5	ສືບສວນ
ການເຄື່ອນໄຫວ	ການ-ເຄື່ອນໄຫວ	4.5	ເຄື່ອນໄຫວ
olympians	olympian-s	4.5	olympian
recommended	recommend-ed	4.5	recommend
ministers	minister-s	4.5	minister
ການລົງທຶນ	ການ-ລົງທຶນ	4.5	ລົງທຶນ
ການເດີນທາງ	ການ-ເດີນທາງ	4.5	ເດີນທາງ
ການວິເຄາະ	ການ-ວິເຄາະ	4.5	ວິເຄາະ
ການໂຄສະນາ	ການ-ໂຄສະນາ	4.5	ໂຄສະນາ
republican	republic-an	4.5	republic
ໃນກາງຊຸມປີ	ໃນ-ກາງຊຸມປີ	4.5	ກາງຊຸມປີ
ອະທິນນາທານາ	ອະທິນນາທ-ານ-າ	3.0	ອະທິນນາທ
ການໄດ້ຍິນ	ການ-ໄດ້ຍິ-ນ	3.0	ໄດ້ຍິ

6.6 Linguistic Interpretation

Automated Insight: The language Lao shows high morphological productivity. The subword models are significantly more efficient than word models, suggesting a rich system of affixation or compounding.

Note on Idiomaticity: The high Idiomaticity Gap suggests a large number of frequent multi-word expressions or formulaic sequences that are statistically distinct from their component parts.

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7. Summary & Recommendations

Production Recommendations

Component	Recommended	Rationale
Tokenizer	64k BPE	Best compression (4.28x)
N-gram	2-gram	Lowest perplexity (2,184)
Markov	Context-4	Highest predictability (98.3%)
Embeddings	100d	Balanced semantic capture and isotropy

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Appendix: Metrics Glossary & Interpretation Guide

This section provides definitions, intuitions, and guidance for interpreting the metrics used throughout this report.

Tokenizer Metrics

Compression Ratio

Definition: The ratio of characters to tokens (chars/token). Measures how efficiently the tokenizer represents text.

Intuition: Higher compression means fewer tokens needed to represent the same text, reducing sequence lengths for downstream models. A 3x compression means ~3 characters per token on average.

What to seek: Higher is generally better for efficiency, but extremely high compression may indicate overly aggressive merging that loses morphological information.

Average Token Length (Fertility)

Definition: Mean number of characters per token produced by the tokenizer.

Intuition: Reflects the granularity of tokenization. Longer tokens capture more context but may struggle with rare words; shorter tokens are more flexible but increase sequence length.

What to seek: Balance between 2-5 characters for most languages. Arabic/morphologically-rich languages may benefit from slightly longer tokens.

Unknown Token Rate (OOV Rate)

Definition: Percentage of tokens that map to the unknown/UNK token, indicating words the tokenizer cannot represent.

Intuition: Lower OOV means better vocabulary coverage. High OOV indicates the tokenizer encounters many unseen character sequences.

What to seek: Below 1% is excellent; below 5% is acceptable. BPE tokenizers typically achieve very low OOV due to subword fallback.

N-gram Model Metrics

Perplexity

Definition: Measures how "surprised" the model is by test data. Mathematically: 2^(cross-entropy). Lower values indicate better prediction.

Intuition: If perplexity is 100, the model is as uncertain as if choosing uniformly among 100 options at each step. A perplexity of 10 means effectively choosing among 10 equally likely options.

What to seek: Lower is better. Perplexity decreases with larger n-grams (more context). Values vary widely by language and corpus size.

Entropy

Definition: Average information content (in bits) needed to encode the next token given the context. Related to perplexity: perplexity = 2^entropy.

Intuition: High entropy means high uncertainty/randomness; low entropy means predictable patterns. Natural language typically has entropy between 1-4 bits per character.

What to seek: Lower entropy indicates more predictable text patterns. Entropy should decrease as n-gram size increases.

Coverage (Top-K)

Definition: Percentage of corpus occurrences explained by the top K most frequent n-grams.

Intuition: High coverage with few patterns indicates repetitive/formulaic text; low coverage suggests diverse vocabulary usage.

What to seek: Depends on use case. For language modeling, moderate coverage (40-60% with top-1000) is typical for natural text.

Markov Chain Metrics

Average Entropy

Definition: Mean entropy across all contexts, measuring average uncertainty in next-word prediction.

Intuition: Lower entropy means the model is more confident about what comes next. Context-1 has high entropy (many possible next words); Context-4 has low entropy (few likely continuations).

What to seek: Decreasing entropy with larger context sizes. Very low entropy (<0.1) indicates highly deterministic transitions.

Branching Factor

Definition: Average number of unique next tokens observed for each context.

Intuition: High branching = many possible continuations (flexible but uncertain); low branching = few options (predictable but potentially repetitive).

What to seek: Branching factor should decrease with context size. Values near 1.0 indicate nearly deterministic chains.

Predictability

Definition: Derived metric: (1 - normalized_entropy) × 100%. Indicates how deterministic the model's predictions are.

Intuition: 100% predictability means the next word is always certain; 0% means completely random. Real text falls between these extremes.

What to seek: Higher predictability for text generation quality, but too high (>98%) may produce repetitive output.

Vocabulary & Zipf's Law Metrics

Zipf's Coefficient

Definition: The slope of the log-log plot of word frequency vs. rank. Zipf's law predicts this should be approximately -1.

Intuition: A coefficient near -1 indicates the corpus follows natural language patterns where a few words are very common and most words are rare.

What to seek: Values between -0.8 and -1.2 indicate healthy natural language distribution. Deviations may suggest domain-specific or artificial text.

R² (Coefficient of Determination)

Definition: Measures how well the linear fit explains the frequency-rank relationship. Ranges from 0 to 1.

Intuition: R² near 1.0 means the data closely follows Zipf's law; lower values indicate deviation from expected word frequency patterns.

What to seek: R² > 0.95 is excellent; > 0.99 indicates near-perfect Zipf adherence typical of large natural corpora.

Vocabulary Coverage

Definition: Cumulative percentage of corpus tokens accounted for by the top N words.

Intuition: Shows how concentrated word usage is. If top-100 words cover 50% of text, the corpus relies heavily on common words.

What to seek: Top-100 covering 30-50% is typical. Higher coverage indicates more repetitive text; lower suggests richer vocabulary.

Word Embedding Metrics

Isotropy

Definition: Measures how uniformly distributed vectors are in the embedding space. Computed as the ratio of minimum to maximum singular values.

Intuition: High isotropy (near 1.0) means vectors spread evenly in all directions; low isotropy means vectors cluster in certain directions, reducing expressiveness.

What to seek: Higher isotropy generally indicates better-quality embeddings. Values > 0.1 are reasonable; > 0.3 is good. Lower-dimensional embeddings tend to have higher isotropy.

Average Norm

Definition: Mean magnitude (L2 norm) of word vectors in the embedding space.

Intuition: Indicates the typical "length" of vectors. Consistent norms suggest stable training; high variance may indicate some words are undertrained.

What to seek: Relatively consistent norms across models. The absolute value matters less than consistency (low std deviation).

Cosine Similarity

Definition: Measures angular similarity between vectors, ranging from -1 (opposite) to 1 (identical direction).

Intuition: Words with similar meanings should have high cosine similarity. This is the standard metric for semantic relatedness in embeddings.

What to seek: Semantically related words should score > 0.5; unrelated words should be near 0. Synonyms often score > 0.7.

t-SNE Visualization

Definition: t-Distributed Stochastic Neighbor Embedding - a dimensionality reduction technique that preserves local structure for visualization.

Intuition: Clusters in t-SNE plots indicate groups of semantically related words. Spread indicates vocabulary diversity; tight clusters suggest semantic coherence.

What to seek: Meaningful clusters (e.g., numbers together, verbs together). Avoid over-interpreting distances - t-SNE preserves local, not global, structure.

General Interpretation Guidelines

1. Compare within model families: Metrics are most meaningful when comparing models of the same type (e.g., 8k vs 64k tokenizer).
2. Consider trade-offs: Better performance on one metric often comes at the cost of another (e.g., compression vs. OOV rate).
3. Context matters: Optimal values depend on downstream tasks. Text generation may prioritize different metrics than classification.
4. Corpus influence: All metrics are influenced by corpus characteristics. Wikipedia text differs from social media or literature.
5. Language-specific patterns: Morphologically rich languages (like Arabic) may show different optimal ranges than analytic languages.

Visualizations Index

Visualization	Description
Tokenizer Compression	Compression ratios by vocabulary size
Tokenizer Fertility	Average token length by vocabulary
Tokenizer OOV	Unknown token rates
Tokenizer Total Tokens	Total tokens by vocabulary
N-gram Perplexity	Perplexity by n-gram size
N-gram Entropy	Entropy by n-gram size
N-gram Coverage	Top pattern coverage
N-gram Unique	Unique n-gram counts
Markov Entropy	Entropy by context size
Markov Branching	Branching factor by context
Markov Contexts	Unique context counts
Zipf's Law	Frequency-rank distribution with fit
Vocab Frequency	Word frequency distribution
Top 20 Words	Most frequent words
Vocab Coverage	Cumulative coverage curve
Embedding Isotropy	Vector space uniformity
Embedding Norms	Vector magnitude distribution
Embedding Similarity	Word similarity heatmap
Nearest Neighbors	Similar words for key terms
t-SNE Words	2D word embedding visualization
t-SNE Sentences	2D sentence embedding visualization
Position Encoding	Encoding method comparison
Model Sizes	Storage requirements
Performance Dashboard	Comprehensive performance overview

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About This Project

Data Source

Models trained on wikipedia-monthly - a monthly snapshot of Wikipedia articles across 300+ languages.

Project

A project by Wikilangs - Open-source NLP models for every Wikipedia language.

Maintainer

Omar Kamali - Omneity Labs

Citation

If you use these models in your research, please cite:

@misc{wikilangs2025,
  author = {Kamali, Omar},
  title = {Wikilangs: Open NLP Models for Wikipedia Languages},
  year = {2025},
  doi = {10.5281/zenodo.18073153},
  publisher = {Zenodo},
  url = {https://huggingface.co/wikilangs}
  institution = {Omneity Labs}
}

License

MIT License - Free for academic and commercial use.

Links

• 🌐 Website: wikilangs.org
• 🤗 Models: huggingface.co/wikilangs
• 📊 Data: wikipedia-monthly
• 👤 Author: Omar Kamali
• 🤝 Sponsor: Featherless AI

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Generated by Wikilangs Models Pipeline

Report Date: 2026-01-10 11:21:00