Mossi - Wikilangs Models
Comprehensive Research Report & Full Ablation Study
This repository contains NLP models trained and evaluated by Wikilangs, specifically on Mossi Wikipedia data. We analyze tokenizers, n-gram models, Markov chains, vocabulary statistics, and word embeddings.
π 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 | 3.339x | 3.34 | 0.2504% | 875,853 |
| 16k | 3.492x | 3.49 | 0.2618% | 837,545 |
| 32k | 3.594x | 3.59 | 0.2695% | 813,821 |
| 64k | 3.679x π | 3.68 | 0.2759% | 794,952 |
Tokenization Examples
Below are sample sentences tokenized with each vocabulary size:
Sample 1: Ne WαΊ½nd yΚΚre, Nimbaan-zoetb-naaba, Nin-zΔnga nimbaan-zoeta
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
| 16k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
| 32k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
| 64k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
Sample 2: SΙ©ngda ne WαΊ½nd yΚΚre, Γ£ndΕ©ni Nimbaan-Zoetb-Naaba la laahir Nimbaan-Zoet-Naaba
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βsΙ©ngda βne βwαΊ½nd βyΚΚre , βΓ£ndΕ©ni βnimbaan - zoetb - ... (+8 more) |
18 |
| 16k | βsΙ©ngda βne βwαΊ½nd βyΚΚre , βΓ£ndΕ©ni βnimbaan - zoetb - ... (+8 more) |
18 |
| 32k | βsΙ©ngda βne βwαΊ½nd βyΚΚre , βΓ£ndΕ©ni βnimbaan - zoetb - ... (+8 more) |
18 |
| 64k | βsΙ©ngda βne βwαΊ½nd βyΚΚre , βΓ£ndΕ©ni βnimbaan - zoetb - ... (+8 more) |
18 |
Sample 3: Ne WαΊ½nd yΚΚre, Nimbaan-zoetb-naaba, Nin-zΔnga nimbaan-zoeta
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
| 16k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
| 32k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
| 64k | βne βwαΊ½nd βyΚΚre , βnimbaan - zoetb - naaba , ... (+6 more) |
16 |
Key Findings
- Best Compression: 64k achieves 3.679x compression
- Lowest UNK Rate: 8k with 0.2504% 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 | 3,615 | 11.82 | 20,744 | 29.4% | 59.7% |
| 2-gram | Subword | 273 π | 8.09 | 2,796 | 65.9% | 99.1% |
| 3-gram | Word | 13,336 | 13.70 | 43,968 | 14.2% | 38.3% |
| 3-gram | Subword | 1,923 | 10.91 | 21,422 | 32.4% | 73.3% |
| 4-gram | Word | 40,697 | 15.31 | 90,918 | 7.5% | 22.5% |
| 4-gram | Subword | 8,329 | 13.02 | 100,573 | 19.4% | 48.8% |
| 5-gram | Word | 44,157 | 15.43 | 75,214 | 6.3% | 18.6% |
| 5-gram | Subword | 22,381 | 14.45 | 221,121 | 13.6% | 36.1% |
Top 5 N-grams by Size
2-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | sαΊ½n yaa |
13,134 |
| 2 | b sαΊ½n |
12,171 |
| 3 | tΙ© b |
8,032 |
| 4 | a sαΊ½n |
6,522 |
| 5 | na n |
6,461 |
3-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | n na n |
2,771 |
| 2 | sαΊ½n boond tΙ© |
2,500 |
| 3 | sαΊ½n na n |
2,163 |
| 4 | b sαΊ½n da |
2,127 |
| 5 | sαΊ½n wa n |
1,587 |
4-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | b sαΊ½n boond tΙ© |
1,290 |
| 2 | sαΊ½n na yΙ©l n |
905 |
| 3 | b sαΊ½n na n |
842 |
| 4 | a sαΊ½n wa n |
720 |
| 5 | sull ning sαΊ½n get |
574 |
5-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | parliament of the 4th republic |
465 |
| 2 | of the 4th republic of |
464 |
| 3 | the 4th republic of ghana |
464 |
| 4 | b sαΊ½n na n maan |
315 |
| 5 | sαΊ½n yaa zaalem n yit |
311 |
2-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | a _ |
226,091 |
| 2 | n _ |
141,998 |
| 3 | _ s |
119,072 |
| 4 | _ n |
113,003 |
| 5 | _ t |
93,570 |
3-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | s αΊ½ n |
63,951 |
| 2 | αΊ½ n _ |
63,904 |
| 3 | _ s αΊ½ |
63,741 |
| 4 | _ a _ |
59,840 |
| 5 | _ n _ |
52,363 |
4-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | s αΊ½ n _ |
63,824 |
| 2 | _ s αΊ½ n |
63,514 |
| 3 | _ y a a |
30,361 |
| 4 | y a a _ |
29,963 |
| 5 | _ l a _ |
23,119 |
5-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ s αΊ½ n _ |
63,440 |
| 2 | _ y a a _ |
29,891 |
| 3 | s αΊ½ n _ y |
17,024 |
| 4 | _ y Κ Κ m |
16,370 |
| 5 | b _ s αΊ½ n |
16,118 |
Key Findings
- Best Perplexity: 2-gram (subword) with 273
- Entropy Trend: Decreases with larger n-grams (more predictable)
- Coverage: Top-1000 patterns cover ~36% 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 | 0.7703 | 1.706 | 5.14 | 57,332 | 23.0% |
| 1 | Subword | 0.8648 | 1.821 | 5.86 | 1,399 | 13.5% |
| 2 | Word | 0.3065 | 1.237 | 1.90 | 294,230 | 69.4% |
| 2 | Subword | 0.8276 | 1.775 | 5.18 | 8,196 | 17.2% |
| 3 | Word | 0.1679 | 1.123 | 1.37 | 557,321 | 83.2% |
| 3 | Subword | 0.8333 | 1.782 | 4.05 | 42,425 | 16.7% |
| 4 | Word | 0.0944 π | 1.068 | 1.17 | 763,192 | 90.6% |
| 4 | Subword | 0.6301 | 1.548 | 2.63 | 171,784 | 37.0% |
Generated Text Samples (Word-based)
Below are text samples generated from each word-based Markov chain model:
Context Size 1:
a dickson sΙ©nga a sαΊ½n yaa kiris neda log koglgΓ£ pΚga neb 0 5 b tallsαΊ½n be zΔ©ig a yΙ© pipi pipi wΓ£ taoor soab a sαΊ½n mik tΙ© palmΙtΓ£ bn pa vΙ© ghana karαΊ½n biiga la a yΓ£ame tΙ© b sαΊ½n wa a piliin sαΊ½n
Context Size 2:
sαΊ½n yaa rap sαΊ½n be volta tαΊ½nga ghana a keem soaba ra yii na baooda taaba yuuyab sαΊ½n tΓ΅e n lebg n wa ne yell sαΊ½n boond tΙ© segΓ£ b sαΊ½n paam ntΙ© b pa bas tΙ© b ra boond b lame tΙ© pa yΙ© sΓ΅ma n tΓ΅e n
Context Size 3:
n na n sΓ΅ng ghana tαΊ½nga neb tΙ© b yΕ© a ne fΙ©Ι©mΓ£ zΔ©ig buud wΚsg na nsαΊ½n boond tΙ© Γ©tni wΓ£ wΙΙngαΊ½ kamΓ£ rutenberg yΙ©Ι© tαΊ½n zαΊ½ms taab karen saamb hekima university college s...sαΊ½n na n zΔ©nd afcon sαΊ½n zΔ©nd kameroΓ΅ wΓ£pΚgαΊ½ b vΙ©Ι©mΓ£ a oteng gyasi yaa kiris ned 1
Context Size 4:
b sαΊ½n boond tΙ© fΓ΅ndΓ£ yaa fΓ΅nd sαΊ½n yaa bαΊ½nd sαΊ½n yaa agaricales tΙ© b yaa bαΊ½nda la bsαΊ½n na yΙ©l n bas a jin ganggang n kαΊ½ng a kang ganggangΓ£ ye b sαΊ½n maan tΚΚm teedΓ£b sαΊ½n na n tΓ΅og a zabrΓ£ yΚΚm a yiib sαΊ½n zΔ©nd senegal tαΊ½nga tΚΚm kaoodbΓ£ taoor soaba sαΊ½n
Generated Text Samples (Subword-based)
Below are text samples generated from each subword-based Markov chain model:
Context Size 1:
_oorvo-bΓ£,_wΔ©-bramulg_b_rinee_r_n_tαΊ½ngerorαΊ½n_nan
Context Size 2:
a_tΙ©_tΓ΅nd_zΓ£gd_wan_yΚΚmd_wΓ£_yaa_n__scul_ham_sαΊ½nganΓ©
Context Size 3:
sαΊ½n_da_gov.gh._yΚΚαΊ½n_tΓ£ag_anda_zΔ©is__sαΊ½n_na_sΓ£_la_sαΊ½n_
Context Size 4:
sαΊ½n_yΙ©Ι©l_n_to-to_no_sαΊ½n_da_tαΊ½nga_la_ki_yaa_woto_lisga_a_t
Key Findings
- Best Predictability: Context-4 (word) with 90.6% predictability
- Branching Factor: Decreases with context size (more deterministic)
- Memory Trade-off: Larger contexts require more storage (171,784 contexts)
- Recommendation: Context-3 or Context-4 for text generation
4. Vocabulary Analysis
Statistics
| Metric | Value |
|---|---|
| Vocabulary Size | 25,483 |
| Total Tokens | 1,059,645 |
| Mean Frequency | 41.58 |
| Median Frequency | 4 |
| Frequency Std Dev | 835.14 |
Most Common Words
| Rank | Word | Frequency |
|---|---|---|
| 1 | a | 70,107 |
| 2 | sαΊ½n | 63,849 |
| 3 | n | 55,318 |
| 4 | b | 41,576 |
| 5 | yaa | 30,095 |
| 6 | wΓ£ | 26,687 |
| 7 | la | 24,541 |
| 8 | tΙ© | 18,168 |
| 9 | ne | 14,910 |
| 10 | be | 10,303 |
Least Common Words (from vocabulary)
| Rank | Word | Frequency |
|---|---|---|
| 1 | grup | 2 |
| 2 | pamiat | 2 |
| 3 | kΙlαΊ½ | 2 |
| 4 | geroy | 2 |
| 5 | yΙlm | 2 |
| 6 | ayensu | 2 |
| 7 | folu | 2 |
| 8 | storms | 2 |
| 9 | kabah | 2 |
| 10 | ayirevire | 2 |
Zipf's Law Analysis
| Metric | Value |
|---|---|
| Zipf Coefficient | 1.2282 |
| RΒ² (Goodness of Fit) | 0.997023 |
| Adherence Quality | excellent |
Coverage Analysis
| Top N Words | Coverage |
|---|---|
| Top 100 | 57.5% |
| Top 1,000 | 81.7% |
| Top 5,000 | 92.6% |
| Top 10,000 | 96.1% |
Key Findings
- Zipf Compliance: RΒ²=0.9970 indicates excellent adherence to Zipf's law
- High Frequency Dominance: Top 100 words cover 57.5% of corpus
- Long Tail: 15,483 words needed for remaining 3.9% 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 | 0.8275 π | 0.3352 | N/A | N/A |
| mono_64d | 64 | 0.6882 | 0.2965 | N/A | N/A |
| mono_128d | 128 | 0.2573 | 0.2728 | N/A | N/A |
| aligned_32d | 32 | 0.8275 | 0.3501 | 0.0400 | 0.2040 |
| aligned_64d | 64 | 0.6882 | 0.2969 | 0.0880 | 0.3240 |
| aligned_128d | 128 | 0.2573 | 0.2710 | 0.1100 | 0.3980 |
Key Findings
- Best Isotropy: mono_32d with 0.8275 (more uniform distribution)
- Semantic Density: Average pairwise similarity of 0.3037. Lower values indicate better semantic separation.
- Alignment Quality: Aligned models achieve up to 11.0% 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 | -0.486 | 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 |
|---|---|
-s |
supreme, spaans, svΔtki |
-a |
adiku, artiste, ampem |
-k |
kΚΚlem, kΚgs, karshon |
-b |
buginese, blige, brobby |
-t |
tuud, tradition, tre |
-p |
pseudostem, parlamentΓ£, ppiri |
-m |
micronesia, mate, molard |
-ma |
mate, malΙΙzi, mante |
Productive Suffixes
| Suffix | Examples |
|---|---|
-e |
citifmonline, supreme, artiste |
-a |
micronesia, natalia, zaba |
-s |
kΚgs, laws, earphones |
-n |
oleson, tradition, vΔn |
-Γ£ |
lillΓ£, parlamentΓ£, baoobΓ£ |
-i |
yendi, ppiri, malΙΙzi |
-r |
gΓΆrenler, glamour, tΓ΅or |
-o |
folklΓ³rico, instituto, klymenko |
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 |
|---|---|---|---|
aand |
2.29x | 31 contexts | maand, naand, vaand |
inis |
1.96x | 27 contexts | minisr, pinisi, phinis |
aren |
2.46x | 12 contexts | karen, arena, kareng |
oore |
1.97x | 16 contexts | boore, poore, moore |
kΓ£se |
1.95x | 15 contexts | kΓ£sem, kΓ£seng, kΓ£sems |
akat |
2.23x | 10 contexts | wakat, wakato, wakatΓ£ |
tame |
2.15x | 11 contexts | votame, kΙ©tame, getame |
atio |
1.95x | 14 contexts | nation, nations, station |
poli |
1.90x | 15 contexts | polis, politk, police |
oond |
1.96x | 13 contexts | moond, boond, boondd |
olit |
2.06x | 10 contexts | politk, polity, politic |
amen |
2.30x | 7 contexts | ameng, amenfi, amenga |
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 |
|---|---|---|---|
-a |
-s |
53 words | alfreds, anas |
-a |
-e |
52 words | ascultare, atske |
-s |
-e |
46 words | sokre, suzanne |
-m |
-s |
44 words | marsalis, morris |
-s |
-s |
43 words | sΙ©ns, seychelles |
-m |
-a |
42 words | moroccoa, menga |
-a |
-n |
42 words | abelian, agyeman |
-p |
-s |
40 words | poems, pΚΚs |
-a |
-a |
39 words | arzΙka, adisa |
-k |
-a |
37 words | koata, kΓ΅ta |
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 |
|---|---|---|---|
| nicholson | nichol-s-on |
7.5 | s |
| neuigkeiten | neuigkeit-e-n |
7.5 | e |
| geleneksel | geleneks-e-l |
7.5 | e |
| charreadas | charread-a-s |
7.5 | a |
| ekonomiya | ekonomi-y-a |
7.5 | y |
| ukrainien | ukraini-e-n |
7.5 | e |
| condiment | condi-me-nt |
7.5 | me |
| unopposed | unoppo-s-ed |
7.5 | s |
| sertipikat | sertipik-a-t |
7.5 | a |
| valensians | valensi-an-s |
6.0 | valensi |
| ecoregions | e-co-regions |
6.0 | regions |
| karαΊ½nsaamb | ka-r-αΊ½nsaamb |
4.5 | αΊ½nsaamb |
| laureates | laureat-es |
4.5 | laureat |
| koordinatΙΙr | ko-ordinatΙΙr |
4.5 | ordinatΙΙr |
| monographs | monograph-s |
4.5 | monograph |
6.6 Linguistic Interpretation
Automated Insight: The language Mossi 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 (3.68x) |
| N-gram | 2-gram | Lowest perplexity (273) |
| Markov | Context-4 | Highest predictability (90.6%) |
| 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) Γ 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.
RΒ² (Coefficient of Determination)
Definition: Measures how well the linear fit explains the frequency-rank relationship. Ranges from 0 to 1.
Intuition: RΒ² near 1.0 means the data closely follows Zipf's law; lower values indicate deviation from expected word frequency patterns.
What to seek: RΒ² > 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
- π Website: wikilangs.org
- π€ Models: huggingface.co/wikilangs
- π Data: wikipedia-monthly
- π€ Author: Omar Kamali
- π€ Sponsor: Featherless AI
Generated by Wikilangs Models Pipeline
Report Date: 2026-01-10 12:34:58



















