Urdu - Wikilangs Models
Comprehensive Research Report & Full Ablation Study
This repository contains NLP models trained and evaluated by Wikilangs, specifically on Urdu 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
1. Tokenizer Evaluation
Results
| Vocab Size | Compression | Avg Token Len | UNK Rate | Total Tokens |
|---|---|---|---|---|
| 8k | 3.434x | 3.44 | 0.1597% | 2,494,826 |
| 16k | 3.731x | 3.74 | 0.1735% | 2,296,340 |
| 32k | 3.936x | 3.95 | 0.1830% | 2,176,646 |
| 64k | 4.066x 🏆 | 4.08 | 0.1891% | 2,107,362 |
Tokenization Examples
Below are sample sentences tokenized with each vocabulary size:
Sample 1: لائژوو چین کا ایک کاؤنٹی سطح شہر جو ژانگجیانگ میں واقع ہے۔ مزید دیکھیے چین فہرست...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | ▁لائ ژ وو ▁چین ▁کا ▁ایک ▁کاؤنٹی ▁سطح ▁شہر ▁جو ... (+21 more) |
31 |
| 16k | ▁لائ ژوو ▁چین ▁کا ▁ایک ▁کاؤنٹی ▁سطح ▁شہر ▁جو ▁ژ ... (+19 more) |
29 |
| 32k | ▁لائ ژوو ▁چین ▁کا ▁ایک ▁کاؤنٹی ▁سطح ▁شہر ▁جو ▁ژانگ ... (+18 more) |
28 |
| 64k | ▁لائ ژوو ▁چین ▁کا ▁ایک ▁کاؤنٹی ▁سطح ▁شہر ▁جو ▁ژانگ ... (+18 more) |
28 |
Sample 2: ساروی پاکستان کا ایک آباد مقام جو ضلع لاہور میں واقع ہے۔ مزید دیکھیے پاکستان پاک...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | ▁سار وی ▁پاکستان ▁کا ▁ایک ▁آباد ▁مقام ▁جو ▁ضلع ▁لاہور ... (+16 more) |
26 |
| 16k | ▁سار وی ▁پاکستان ▁کا ▁ایک ▁آباد ▁مقام ▁جو ▁ضلع ▁لاہور ... (+16 more) |
26 |
| 32k | ▁سار وی ▁پاکستان ▁کا ▁ایک ▁آباد ▁مقام ▁جو ▁ضلع ▁لاہور ... (+16 more) |
26 |
| 64k | ▁سار وی ▁پاکستان ▁کا ▁ایک ▁آباد ▁مقام ▁جو ▁ضلع ▁لاہور ... (+16 more) |
26 |
Sample 3: انڈونیشیا کی ثقافت سے مراد انڈونیشیا کا ثقافتی ورثہ ہے۔ حوالہ جات ثقافت مشرقی ای...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | ▁انڈونیشیا ▁کی ▁ثقافت ▁سے ▁مراد ▁انڈونیشیا ▁کا ▁ثقافتی ▁ورثہ ▁ہے۔ ... (+6 more) |
16 |
| 16k | ▁انڈونیشیا ▁کی ▁ثقافت ▁سے ▁مراد ▁انڈونیشیا ▁کا ▁ثقافتی ▁ورثہ ▁ہے۔ ... (+6 more) |
16 |
| 32k | ▁انڈونیشیا ▁کی ▁ثقافت ▁سے ▁مراد ▁انڈونیشیا ▁کا ▁ثقافتی ▁ورثہ ▁ہے۔ ... (+6 more) |
16 |
| 64k | ▁انڈونیشیا ▁کی ▁ثقافت ▁سے ▁مراد ▁انڈونیشیا ▁کا ▁ثقافتی ▁ورثہ ▁ہے۔ ... (+6 more) |
16 |
Key Findings
- Best Compression: 64k achieves 4.066x compression
- Lowest UNK Rate: 8k with 0.1597% unknown tokens
- Trade-off: Larger vocabularies improve compression but increase model size
- Recommendation: 32k vocabulary provides optimal balance for production use
2. N-gram Model Evaluation
Results
| N-gram | Variant | Perplexity | Entropy | Unique N-grams | Top-100 Coverage | Top-1000 Coverage |
|---|---|---|---|---|---|---|
| 2-gram | Word | 71,880 | 16.13 | 920,952 | 12.1% | 28.0% |
| 2-gram | Subword | 407 🏆 | 8.67 | 31,986 | 59.9% | 96.3% |
| 3-gram | Word | 315,178 | 18.27 | 2,297,981 | 8.3% | 17.4% |
| 3-gram | Subword | 3,547 | 11.79 | 203,673 | 25.5% | 63.2% |
| 4-gram | Word | 765,780 | 19.55 | 4,319,755 | 7.4% | 14.2% |
| 4-gram | Subword | 19,593 | 14.26 | 1,069,845 | 12.6% | 37.0% |
| 5-gram | Word | 617,009 | 19.23 | 3,316,122 | 7.9% | 15.7% |
| 5-gram | Subword | 75,628 | 16.21 | 3,267,447 | 7.4% | 25.5% |
Top 5 N-grams by Size
2-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | کے لیے |
246,197 |
| 2 | حوالہ جات |
212,286 |
| 3 | واقع ہے |
138,739 |
| 4 | مزید دیکھیے |
134,662 |
| 5 | ہے اور |
134,251 |
3-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | میں واقع ہے |
98,697 |
| 2 | ہے مزید دیکھیے |
91,225 |
| 3 | ریاستہائے متحدہ امریکا |
75,905 |
| 4 | شہر حوالہ جات |
70,046 |
| 5 | کے شہر حوالہ |
69,949 |
4-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | کے شہر حوالہ جات |
69,947 |
| 2 | ڈیٹا سے مختلف مختصر |
60,477 |
| 3 | سے مختلف مختصر وضاحت |
60,477 |
| 4 | میں واقع ہے تفصیلات |
57,274 |
| 5 | واقع ہے مزید دیکھیے |
56,176 |
5-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | ڈیٹا سے مختلف مختصر وضاحت |
60,477 |
| 2 | مطابقت رکھنے والی مختصر تفصیل |
36,597 |
| 3 | ڈیٹا سے مطابقت رکھنے والی |
36,597 |
| 4 | سے مطابقت رکھنے والی مختصر |
36,597 |
| 5 | ریاستہائے متحدہ امریکا کا ایک |
32,162 |
2-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ ک |
8,939,155 |
| 2 | ے _ |
7,506,929 |
| 3 | ی _ |
7,229,403 |
| 4 | _ ا |
6,895,736 |
| 5 | _ م |
5,580,612 |
3-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | ی ں _ |
2,526,926 |
| 2 | ک ے _ |
2,439,009 |
| 3 | _ ک ے |
2,399,929 |
| 4 | _ ک ی |
2,309,611 |
| 5 | _ م ی |
2,222,538 |
4-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ ک ے _ |
2,395,195 |
| 2 | م ی ں _ |
1,913,836 |
| 3 | _ م ی ں |
1,894,953 |
| 4 | _ ک ی _ |
1,654,644 |
| 5 | _ ا و ر |
1,206,959 |
5-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ م ی ں _ |
1,841,071 |
| 2 | _ ا و ر _ |
1,180,320 |
| 3 | _ ا ی ک _ |
540,019 |
| 4 | _ ہ ے ۔ _ |
533,595 |
| 5 | ن _ ک ے _ |
281,812 |
Key Findings
- Best Perplexity: 2-gram (subword) with 407
- Entropy Trend: Decreases with larger n-grams (more predictable)
- Coverage: Top-1000 patterns cover ~26% of corpus
- Recommendation: 4-gram or 5-gram for best predictive performance
3. Markov Chain Evaluation
Results
| Context | Variant | Avg Entropy | Perplexity | Branching Factor | Unique Contexts | Predictability |
|---|---|---|---|---|---|---|
| 1 | Word | 0.7878 | 1.726 | 10.02 | 931,321 | 21.2% |
| 1 | Subword | 1.0778 | 2.111 | 8.71 | 12,123 | 0.0% |
| 2 | Word | 0.4142 | 1.333 | 2.63 | 9,325,685 | 58.6% |
| 2 | Subword | 0.7107 | 1.637 | 4.70 | 105,552 | 28.9% |
| 3 | Word | 0.2036 | 1.152 | 1.51 | 24,486,673 | 79.6% |
| 3 | Subword | 0.6567 | 1.576 | 3.92 | 496,416 | 34.3% |
| 4 | Word | 0.0977 🏆 | 1.070 | 1.19 | 36,918,721 | 90.2% |
| 4 | Subword | 0.6391 | 1.557 | 3.25 | 1,947,168 | 36.1% |
Generated Text Samples (Word-based)
Below are text samples generated from each word-based Markov chain model:
Context Size 1:
کے خلاف شمالی افریقی ارکان پارلیمنٹ جان جیکب آباد مقامات ڈیٹا سے قبل مسیح rishi 24میں اس پر پہچان ایک وسیع تحقیق کی جاتی ہے اور دیگر نے بنا مزید دیکھیےکی سپریم کورٹ سی پی سی اے حسینہ اور 626 0 126 نے مسترد کرتے ہوئے
Context Size 2:
کے لیے دو فرسٹ کلاس کرکٹ میں ان کی نمائندگی کرتے ہیں اور طنز کرتے اور حقانیتحوالہ جات بیرونی روابط طرطلیان کا معما بنی ہوئی ایک ترقی یافتہ ڈویژن فور کے لیے حملہواقع ہے مزید دیکھیے لتھووینیا فہرست لتھووینیا کے نامکمل مضامین ڈیٹا سے مختلف مختصر وضاحت کی پیدائشیں
Context Size 3:
میں واقع ہے تفصیلات ییپچس ضلع کا رقبہ 53 944 مربع کلومیٹر ہے اس کی مجموعی آبادی 6ہے مزید دیکھیے جرمنی کی ریاستیں 16 بھارت کی ریاستیں بلحاظ آبادی حوالہ جات میں قائم ہونے والےریاستہائے متحدہ امریکا ریاستہائے متحدہ امریکا کا ایک ٹاؤن شپ جو کلنٹن کاؤنٹی اوہائیو اوہائیو 61 310 ...
Context Size 4:
کے شہر حوالہ جات میں آباد ہونے والے مقامات ڈیٹا سے مختلف مختصر وضاحت کے آباد مقامات میں مرگڈیٹا سے مختلف مختصر وضاحت مزاحیہ ڈراما فلمیں فلمیں متحدہ میں زنا کے بارے میں فلمیں فلمیں سے تخلیقمیں واقع ہے تفصیلات لا شاپیل این والگوڈیمار کا رقبہ 108 02 مربع کلومیٹر ہے اور اس کی مجموعی
Generated Text Samples (Subword-based)
Below are text samples generated from each subword-based Markov chain model:
Context Size 1:
_16_دیکاس_مد_کے_ا_اتھروساہے_لے۔_یں_tad_ا_نیا_205
Context Size 2:
_کی_پان_ال_ہور_برے_ان_میں_معا_مغربی_ول_گار_پیدارکھی
Context Size 3:
یں_کا_کورپینیجرینڈکے_بلندیر_بِکری_علی_کے_تھے۔_ابھ_انھوں
Context Size 4:
_کے_نتیجے_میں_واقع_میں_جہاں_i_tehsil_w_میں_وشون-شوگر_پار،
Key Findings
- Best Predictability: Context-4 (word) with 90.2% predictability
- Branching Factor: Decreases with context size (more deterministic)
- Memory Trade-off: Larger contexts require more storage (1,947,168 contexts)
- Recommendation: Context-3 or Context-4 for text generation
4. Vocabulary Analysis
Statistics
| Metric | Value |
|---|---|
| Vocabulary Size | 395,742 |
| Total Tokens | 58,544,950 |
| Mean Frequency | 147.94 |
| Median Frequency | 4 |
| Frequency Std Dev | 7177.12 |
Most Common Words
| Rank | Word | Frequency |
|---|---|---|
| 1 | کے | 2,399,956 |
| 2 | میں | 1,897,386 |
| 3 | کی | 1,727,992 |
| 4 | اور | 1,185,297 |
| 5 | ہے | 1,085,895 |
| 6 | سے | 991,149 |
| 7 | کا | 802,866 |
| 8 | نے | 660,570 |
| 9 | اس | 581,153 |
| 10 | پر | 570,105 |
Least Common Words (from vocabulary)
| Rank | Word | Frequency |
|---|---|---|
| 1 | yarns | 2 |
| 2 | anika | 2 |
| 3 | dailystar | 2 |
| 4 | دامنیوں | 2 |
| 5 | دریاچۂ | 2 |
| 6 | murgap | 2 |
| 7 | دیمقراطیت | 2 |
| 8 | الممتنعة | 2 |
| 9 | کرداراے | 2 |
| 10 | قیطابای | 2 |
Zipf's Law Analysis
| Metric | Value |
|---|---|
| Zipf Coefficient | 1.1596 |
| R² (Goodness of Fit) | 0.989996 |
| Adherence Quality | excellent |
Coverage Analysis
| Top N Words | Coverage |
|---|---|
| Top 100 | 40.8% |
| Top 1,000 | 67.7% |
| Top 5,000 | 84.7% |
| Top 10,000 | 89.9% |
Key Findings
- Zipf Compliance: R²=0.9900 indicates excellent adherence to Zipf's law
- High Frequency Dominance: Top 100 words cover 40.8% of corpus
- Long Tail: 385,742 words needed for remaining 10.1% coverage
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 | 0.7965 🏆 | 0.3746 | N/A | N/A |
| mono_64d | 64 | 0.7804 | 0.3072 | N/A | N/A |
| mono_128d | 128 | 0.7411 | 0.2584 | N/A | N/A |
| aligned_32d | 32 | 0.7965 | 0.3667 | 0.0900 | 0.3980 |
| aligned_64d | 64 | 0.7804 | 0.3243 | 0.1900 | 0.5220 |
| aligned_128d | 128 | 0.7411 | 0.2599 | 0.2640 | 0.6360 |
Key Findings
- Best Isotropy: mono_32d with 0.7965 (more uniform distribution)
- Semantic Density: Average pairwise similarity of 0.3152. Lower values indicate better semantic separation.
- Alignment Quality: Aligned models achieve up to 26.4% R@1 in cross-lingual retrieval.
- Recommendation: 128d aligned for best cross-lingual performance
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 | -0.387 | Low formulaic 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 |
|---|---|
-ال |
الازہار, الحسينی, الكرخی |
-ا |
الازہار, اعادی, اسکن |
-م |
موزولینی, مشہورہ, میلوم |
-ب |
بیٹاہے, بمبی, بدیشگرام |
-س |
سکھانے, سگاچے, سووموٹو |
-ک |
کورینتینے, کتابتِ, کٹمور |
-و |
وملل, وففینگے, وولڈز |
-ت |
تبصروں, تحس, ترسیلات |
Productive Suffixes
| Suffix | Examples |
|---|---|
-ی |
نمامی, اعادی, بمبی |
-ا |
آئیڈیلا, چھیڈا, سنگڑا |
-ن |
اسکن, ڑککن, لعبدالرحمن |
-s |
anthonys, carpets, condoles |
-n |
usenon, areairon, bannerman |
-e |
linkage, lafitte, ampère |
-ں |
پنجابیوں, بیروتژاں, تبصروں |
-ر |
الازہار, کٹمور, خائر |
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 |
|---|---|---|---|
ھارت |
2.29x | 63 contexts | ہھارت, پھارت, دھارت |
مریک |
2.26x | 41 contexts | امریک, مریکی, مریکہ |
اؤنٹ |
2.16x | 43 contexts | ماؤنٹ, گاؤنٹ, کاؤنٹ |
کاؤن |
2.21x | 39 contexts | کاؤنا, کاؤنی, کاؤنٹ |
اریخ |
1.86x | 54 contexts | فاریخ, تاریخ, تاریخٰ |
لاقو |
2.48x | 18 contexts | علاقو, الاقو, لاقوۃ |
ھلاڑ |
2.91x | 11 contexts | ڈھلاڑ, کھلاڑ, لھلاڑی |
اقوا |
2.16x | 27 contexts | اقوام, جاقوا, اقوال |
ختلف |
2.31x | 20 contexts | اختلف, يختلف, مختلف |
ختصر |
2.07x | 23 contexts | اختصر, مختصر, مختصرا |
الاق |
1.77x | 39 contexts | الاقو, الاقصي, الاقصى |
تحدہ |
2.47x | 11 contexts | متحدہ, 1متحدہ, المتحدہ |
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 |
|---|---|---|---|
-ال |
-ی |
59 words | النفیسی, الأولی |
-ا |
-ا |
45 words | اورلینزلوویزیانا, اماٹیلا |
-ا |
-ی |
43 words | انڈیانامیامی, النفیسی |
-س |
-ی |
35 words | سریمورالی, سیارچوی |
-ک |
-ی |
32 words | کندی, کولاتیری |
-ال |
-ن |
31 words | الوالدين, الیکزاندرپشکن |
-ال |
-ہ |
28 words | العربیہ, السیارہ |
-م |
-ی |
26 words | مہرؤلی, مورنسی |
-ب |
-ی |
24 words | بحیری, بریطانی |
-ا |
-ن |
23 words | ابوالرین, انبان |
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 |
|---|---|---|---|
| ایکسیلنسی | ایکسیلن-س-ی |
7.5 | س |
| ریٹروگریڈ | ریٹروگر-ی-ڈ |
7.5 | ی |
| گراؤنڈبیونس | گراؤنڈبیو-ن-س |
7.5 | ن |
| کوستنجویکانہ | کوستنجویک-ان-ہ |
7.5 | ان |
| اورتعلیمی | اور-تعلیم-ی |
6.0 | تعلیم |
| مالمزبیری | م-الم-زبیری |
6.0 | زبیری |
| composers | composer-s |
4.5 | composer |
| نصیرآبادی | نصیرآباد-ی |
4.5 | نصیرآباد |
| تھیوبالڈس | تھیوبالڈ-س |
4.5 | تھیوبالڈ |
| ہائیڈریٹس | ہائیڈریٹ-س |
4.5 | ہائیڈریٹ |
| پیرالمپکس | پیرالمپک-س |
4.5 | پیرالمپک |
| dwellings | dwelling-s |
4.5 | dwelling |
| violations | violation-s |
4.5 | violation |
| positional | position-al |
4.5 | position |
| oscillators | oscillator-s |
4.5 | oscillator |
6.6 Linguistic Interpretation
Automated Insight: The language Urdu shows high morphological productivity. The subword models are significantly more efficient than word models, suggesting a rich system of affixation or compounding.
7. Summary & Recommendations
Production Recommendations
| Component | Recommended | Rationale |
|---|---|---|
| Tokenizer | 64k BPE | Best compression (4.07x) |
| N-gram | 2-gram | Lowest perplexity (407) |
| Markov | Context-4 | Highest predictability (90.2%) |
| Embeddings | 100d | Balanced semantic capture and isotropy |
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
- Compare within model families: Metrics are most meaningful when comparing models of the same type (e.g., 8k vs 64k tokenizer).
- Consider trade-offs: Better performance on one metric often comes at the cost of another (e.g., compression vs. OOV rate).
- Context matters: Optimal values depend on downstream tasks. Text generation may prioritize different metrics than classification.
- Corpus influence: All metrics are influenced by corpus characteristics. Wikipedia text differs from social media or literature.
- 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 |
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
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
Generated by Wikilangs Models Pipeline
Report Date: 2026-01-11 06:46:29



















