Tachelhit - Wikilangs Models
Comprehensive Research Report & Full Ablation Study
This repository contains NLP models trained and evaluated by Wikilangs, specifically on Tachelhit 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 | 3.016x | 3.02 | 1.3945% | 407,897 |
| 16k | 3.301x | 3.30 | 1.5260% | 372,731 |
| 32k | 3.556x | 3.56 | 1.6440% | 345,980 |
| 64k | 3.819x π | 3.82 | 1.7653% | 322,212 |
Tokenization Examples
Below are sample sentences tokenized with each vocabulary size:
Sample 1: Talggut neΙ£ Algu tga yat tasklut ur iskaren awd yat ugummu, tesker ifrawen zund ...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βtal gg ut βneΙ£ βal gu βtga βyat βtas klut ... (+29 more) |
39 |
| 16k | βtal ggut βneΙ£ βalgu βtga βyat βtasklut βur βiskar en ... (+22 more) |
32 |
| 32k | βtalggut βneΙ£ βalgu βtga βyat βtasklut βur βiskaren βawd βyat ... (+20 more) |
30 |
| 64k | βtalggut βneΙ£ βalgu βtga βyat βtasklut βur βiskaren βawd βyat ... (+19 more) |
29 |
Sample 2: 1 000 iga yan umαΈan imqquαΉn, ism ns s tmaziΙ£t igat ifαΈ (s tfinaΙ£ : β΅β΄Όβ΄Ή). Msmun a...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | β 1 β 0 0 0 βiga βyan βumαΈan βimqquαΉn ... (+30 more) |
40 |
| 16k | β 1 β 0 0 0 βiga βyan βumαΈan βimqquαΉn ... (+29 more) |
39 |
| 32k | β 1 β 0 0 0 βiga βyan βumαΈan βimqquαΉn ... (+29 more) |
39 |
| 64k | β 1 β 0 0 0 βiga βyan βumαΈan βimqquαΉn ... (+29 more) |
39 |
Sample 3: Iga Q yan sg iskkiln n ugmmay alatin n tmaziΙ£t. TisaΙ£ulin amaziΙ£ tamaziΙ£t
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βiga βq βyan βsg βiskkiln βn βugmmay βalatin βn βtmaziΙ£t ... (+4 more) |
14 |
| 16k | βiga βq βyan βsg βiskkiln βn βugmmay βalatin βn βtmaziΙ£t ... (+4 more) |
14 |
| 32k | βiga βq βyan βsg βiskkiln βn βugmmay βalatin βn βtmaziΙ£t ... (+4 more) |
14 |
| 64k | βiga βq βyan βsg βiskkiln βn βugmmay βalatin βn βtmaziΙ£t ... (+4 more) |
14 |
Key Findings
- Best Compression: 64k achieves 3.819x compression
- Lowest UNK Rate: 8k with 1.3945% 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 | 1,027 | 10.00 | 23,236 | 45.7% | 81.7% |
| 2-gram | Subword | 255 π | 7.99 | 3,781 | 68.8% | 99.0% |
| 3-gram | Word | 1,698 | 10.73 | 46,052 | 39.0% | 76.4% |
| 3-gram | Subword | 1,284 | 10.33 | 29,091 | 35.1% | 84.7% |
| 4-gram | Word | 3,109 | 11.60 | 90,307 | 35.2% | 68.9% |
| 4-gram | Subword | 3,344 | 11.71 | 117,787 | 23.5% | 73.6% |
| 5-gram | Word | 3,900 | 11.93 | 100,603 | 35.2% | 65.7% |
| 5-gram | Subword | 5,685 | 12.47 | 238,802 | 18.6% | 68.5% |
Top 5 N-grams by Size
2-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | tgmiαΈi n |
30,047 |
| 2 | n usggΚ·as |
27,406 |
| 3 | umαΈan n |
26,921 |
| 4 | n imzdaΙ£n |
25,250 |
| 5 | tlkm tgmiαΈi |
24,096 |
3-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | tlkm tgmiαΈi n |
24,096 |
| 2 | tamattayt n usΙ£iws |
16,122 |
| 3 | tasmirit tamattayt n |
15,740 |
| 4 | umαΈan n imzdaΙ£n |
14,946 |
| 5 | g tlkm tgmiαΈi |
12,050 |
4-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | tasmirit tamattayt n usΙ£iws |
15,739 |
| 2 | g tlkm tgmiαΈi n |
12,050 |
| 3 | ad i trfiqt n |
8,924 |
| 4 | uαΈwwaαΉ ad i trfiqt |
8,917 |
| 5 | umαΈan n imzdaΙ£n nns |
8,916 |
5-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | uαΈwwaαΉ ad i trfiqt n |
8,916 |
| 2 | amatay n imzdaΙ£n tasmirit tamattayt |
8,910 |
| 3 | imzdaΙ£n tasmirit tamattayt n usΙ£iws |
8,910 |
| 4 | n imzdaΙ£n tasmirit tamattayt n |
8,910 |
| 5 | ilkm umαΈan n imzdaΙ£n nns |
8,904 |
2-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | n _ |
653,867 |
| 2 | _ n |
401,914 |
| 3 | _ t |
358,373 |
| 4 | _ i |
253,323 |
| 5 | t a |
205,156 |
3-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ n _ |
294,487 |
| 2 | _ t a |
132,536 |
| 3 | n _ t |
104,627 |
| 4 | a n _ |
103,501 |
| 5 | _ Ι£ _ |
101,865 |
4-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ n _ u |
84,430 |
| 2 | t _ n _ |
67,376 |
| 3 | _ n _ i |
61,495 |
| 4 | _ n _ t |
56,122 |
| 5 | n _ u s |
52,239 |
5-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ n _ u s |
51,413 |
| 2 | m z d a Ι£ |
46,710 |
| 3 | g g Κ· a s |
34,963 |
| 4 | s g g Κ· a |
34,938 |
| 5 | _ n n a _ |
34,315 |
Key Findings
- Best Perplexity: 2-gram (subword) with 255
- Entropy Trend: Decreases with larger n-grams (more predictable)
- Coverage: Top-1000 patterns cover ~68% 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 | 0.6330 | 1.551 | 4.06 | 76,235 | 36.7% |
| 1 | Subword | 1.2937 | 2.452 | 10.38 | 803 | 0.0% |
| 2 | Word | 0.2598 | 1.197 | 1.65 | 308,778 | 74.0% |
| 2 | Subword | 1.0718 | 2.102 | 6.52 | 8,338 | 0.0% |
| 3 | Word | 0.0839 | 1.060 | 1.19 | 508,428 | 91.6% |
| 3 | Subword | 0.8300 | 1.778 | 3.82 | 54,347 | 17.0% |
| 4 | Word | 0.0475 π | 1.033 | 1.13 | 601,160 | 95.2% |
| 4 | Subword | 0.5641 | 1.478 | 2.43 | 207,735 | 43.6% |
Generated Text Samples (Word-based)
Below are text samples generated from each word-based Markov chain model:
Context Size 1:
n ayt twayya nna dar irgazn d amatay n usggΚ·as niΙ£ uggar Ι£ Ιin ijri sΙ£ uαΈwwaαΉ innazwan yili Ι£ lmΙ£rib iαΈfaαΉ uαΈwwaαΉ ad i twuri tannayin tisaΙ£ulin Ι£ llan 4d 11 n tarwuri 2 ig unammas n tznit tamnaαΈt n iαΈuαΉan ilkm wawtay nnsn iαΊαΈiαΉn
Context Size 2:
tgmiαΈi n uslmd 92 86 gr irban d trbatin nna dar 15 n usggΚ·as dΓ©mographiques et socion usggΚ·as dΓ©mographiques et socio Γ©conomiques de la population rurale hors nomades par douar selon l...umαΈan n imzdaΙ£n n usun ad 20 n iαΈuαΉan ilkm umαΈan n twjiwin s 32 7 gr
Context Size 3:
tlkm tgmiαΈi n uslmd 100 gr irban d trbatin nna dar gr 6 d 11 n usggΚ·as Ι£tamattayt n usΙ£iws tannayin tisaΙ£ulin Ι£ lmΙ£rib Ι£ tsga n lαΈ₯uz n lαΈ₯uz n lαΈ₯uz n lαΈ₯uz ntasmirit tamattayt n usΙ£iws Ι£ iga umαΈan n imawaαΈn 224 n umzdaΙ£ gisn 581 n iwtman d 329
Context Size 4:
tasmirit tamattayt n usΙ£iws Ι£ iga umαΈan n imawaαΈn 236 n umzdaΙ£ gisn 110 n iwtman d 101 ng tlkm tgmiαΈi n uslmd 89 66 gr irban d trbatin nna dar gr 6 d 11 n usggΚ·asad i trfiqt n ayt iΙzman nna Ι£ llan 4 n iαΈuαΉan ilkm umαΈan n imzdaΙ£n nns 251 n
Generated Text Samples (Subword-based)
Below are text samples generated from each subword-based Markov chain model:
Context Size 1:
_5_wtaαΉsΙ£_t_tanaaαΈas_tm_aΙ£naphonnn_nn_puriquriΙ£_
Context Size 2:
n_muαΈwwawtmas_soc_n_et_tamklattamk_tawtmadin_tlkm_u
Context Size 3:
_n_imzdaΙ£n_nit_soc_tarwurin_i_trfiqtn_tawuri._tluαΈ₯arch
Context Size 4:
_n_usΙ£iws._aαΉcif,_1t_n_iwtman_d_23.95__n_imzdaΙ£n_n_iwtman
Key Findings
- Best Predictability: Context-4 (word) with 95.2% predictability
- Branching Factor: Decreases with context size (more deterministic)
- Memory Trade-off: Larger contexts require more storage (207,735 contexts)
- Recommendation: Context-3 or Context-4 for text generation
4. Vocabulary Analysis
Statistics
| Metric | Value |
|---|---|
| Vocabulary Size | 31,610 |
| Total Tokens | 2,378,642 |
| Mean Frequency | 75.25 |
| Median Frequency | 4 |
| Frequency Std Dev | 1969.69 |
Most Common Words
| Rank | Word | Frequency |
|---|---|---|
| 1 | n | 294,685 |
| 2 | Ι£ | 101,988 |
| 3 | d | 64,374 |
| 4 | s | 34,997 |
| 5 | nna | 34,361 |
| 6 | imzdaΙ£n | 31,398 |
| 7 | dar | 30,865 |
| 8 | gr | 30,721 |
| 9 | tgmiαΈi | 30,050 |
| 10 | usggΚ·as | 28,210 |
Least Common Words (from vocabulary)
| Rank | Word | Frequency |
|---|---|---|
| 1 | tdarwinit | 2 |
| 2 | talmuqqdimt | 2 |
| 3 | ttawnn | 2 |
| 4 | taggrgist | 2 |
| 5 | umdgar | 2 |
| 6 | uqαΉiαΈ | 2 |
| 7 | dearborn | 2 |
| 8 | ghosts | 2 |
| 9 | tremblay | 2 |
| 10 | tmmndl | 2 |
Zipf's Law Analysis
| Metric | Value |
|---|---|
| Zipf Coefficient | 1.2849 |
| RΒ² (Goodness of Fit) | 0.988016 |
| Adherence Quality | excellent |
Coverage Analysis
| Top N Words | Coverage |
|---|---|
| Top 100 | 69.6% |
| Top 1,000 | 90.6% |
| Top 5,000 | 95.6% |
| Top 10,000 | 97.3% |
Key Findings
- Zipf Compliance: RΒ²=0.9880 indicates excellent adherence to Zipf's law
- High Frequency Dominance: Top 100 words cover 69.6% of corpus
- Long Tail: 21,610 words needed for remaining 2.7% 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 | 0.7173 | 0.3723 | N/A | N/A |
| mono_64d | 64 | 0.5707 | 0.3238 | N/A | N/A |
| mono_128d | 128 | 0.2225 | 0.3121 | N/A | N/A |
| aligned_32d | 32 | 0.7173 π | 0.3624 | 0.0140 | 0.0980 |
| aligned_64d | 64 | 0.5707 | 0.3343 | 0.0280 | 0.1200 |
| aligned_128d | 128 | 0.2225 | 0.3186 | 0.0400 | 0.1960 |
Key Findings
- Best Isotropy: aligned_32d with 0.7173 (more uniform distribution)
- Semantic Density: Average pairwise similarity of 0.3372. Lower values indicate better semantic separation.
- Alignment Quality: Aligned models achieve up to 4.0% 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 | -0.041 | 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 |
|---|---|
-t |
tugt, tattuyt, tyyuga |
-i |
issiks, imαΊyann, izdg |
-ta |
tattuyt, taryal, tamaαΊuαΊt |
-a |
azdawan, amazΙ£, afnsu |
-u |
utin, uswaΙ£, uzzugz |
-l |
lmαΉ£alαΈ₯a, lbkr, lmujawharat |
-ti |
tizrigin, tidzi, timdst |
-m |
maskurt, mαΈ₯da, mmaggarn |
Productive Suffixes
| Suffix | Examples |
|---|---|
-n |
utin, azdawan, tΙ£mriwin |
-t |
tugt, tattuyt, trifiyt |
-a |
tyyuga, mαΈ₯da, tssa |
-in |
utin, tΙ£mriwin, Ι£win |
-s |
issiks, chaouis, nations |
-i |
inlbi, uΙ£ri, igiddi |
-e |
conduite, historique, dΓ©chirΓ©e |
-an |
azdawan, zyyan, franslyan |
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 |
|---|---|---|---|
adda |
1.65x | 52 contexts | addad, wadda, jadda |
ggΚ·a |
1.63x | 43 contexts | aggΚ·a, αΈ₯ggΚ·a, zggΚ·ar |
ggar |
1.94x | 22 contexts | iggar, uggar, ggarn |
ugga |
1.94x | 21 contexts | uggar, uggan, yugga |
wuri |
1.68x | 30 contexts | twuri, iswuri, swurin |
tion |
2.09x | 14 contexts | notion, action, nation |
Ι£rib |
1.80x | 20 contexts | aΙ£rib, mΙ£rib, lΙ£ribi |
lati |
1.61x | 27 contexts | latin, latif, mulati |
matt |
1.60x | 26 contexts | matta, tmatti, umatta |
mΙ£ri |
1.79x | 13 contexts | tmΙ£ri, mΙ£rib, imΙ£ri |
atio |
1.86x | 8 contexts | nation, nations, national |
mata |
1.45x | 14 contexts | amata, smata, umata |
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 |
|---|---|---|---|
-t |
-t |
610 words | tifrirt, tdrfit |
-i |
-n |
465 words | ittmttatn, ibαΉbbachn |
-t |
-n |
321 words | ttyussanin, tigtfulin |
-t |
-in |
263 words | ttyussanin, tigtfulin |
-l |
-a |
84 words | lbαΉaαΉla, lΙnabsa |
-t |
-a |
65 words | tiαΉαΉuyαΉ£a, tzuna |
-i |
-an |
45 words | inultan, ilawan |
-a |
-i |
39 words | adarazi, abriαΉani |
-a |
-n |
38 words | agwensan, agaman |
-l |
-t |
32 words | lfwarat, lfuqqiyyat |
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 |
|---|---|---|---|
| tasnmαΈant | tasnmαΈ-an-t |
7.5 | an |
| africaine | africa-in-e |
7.5 | in |
| ttyawssannin | ttyawssan-n-in |
7.5 | n |
| ittyurnan | ittyur-n-an |
7.5 | n |
| ittusΙ£αΊnn | ittusΙ£αΊ-n-n |
7.5 | n |
| zzuzzarnit | zzuzzar-n-it |
7.5 | n |
| tutlayyin | tutlay-y-in |
7.5 | y |
| ttaggΚ·anin | ttaggΚ·a-n-in |
7.5 | n |
| marocaines | maroca-in-es |
7.5 | in |
| government | governme-n-t |
7.5 | n |
| ttussiαΈannt | ttussiαΈ-an-nt |
7.5 | an |
| ittyawstay | ittyaws-t-ay |
7.5 | t |
| patrimoine | patrimo-in-e |
7.5 | in |
| ittuzdaΙ£n | it-tu-zdaΙ£n |
6.0 | zdaΙ£n |
| tinsmunin | ti-nsmun-in |
6.0 | nsmun |
6.6 Linguistic Interpretation
Automated Insight: The language Tachelhit 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 (3.82x) |
| N-gram | 2-gram | Lowest perplexity (255) |
| Markov | Context-4 | Highest predictability (95.2%) |
| 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) 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 20:02:34



















