Fon - Wikilangs Models
Comprehensive Research Report & Full Ablation Study
This repository contains NLP models trained and evaluated by Wikilangs, specifically on Fon 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 | 3.633x | 3.64 | 0.1627% | 178,834 |
| 16k | 3.846x | 3.85 | 0.1723% | 168,913 |
| 32k | 4.057x | 4.06 | 0.1817% | 160,142 |
| 64k | 4.124x π | 4.13 | 0.1847% | 157,541 |
Tokenization Examples
Below are sample sentences tokenized with each vocabulary size:
Sample 1: Koffi Danger, ΙΜ nyΓ malΓ nhwlΙΜnvlΙΜtΙΜ BenΙΙ tΙn ΙΓ© wΙ bΙ Γ¨ jΓ¬ i ΙΓ² ΙΓ² GbΙΜxikΙ...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βkoffi βdan ger , βΙΜ βnyΓ βmalΓ nhwlΙΜnvlΙΜ tΙΜ βbenΙΙ βtΙn ... (+19 more) |
29 |
| 16k | βkoffi βdanger , βΙΜ βnyΓ βmalΓ nhwlΙΜnvlΙΜ tΙΜ βbenΙΙ βtΙn βΙΓ© ... (+18 more) |
28 |
| 32k | βkoffi βdanger , βΙΜ βnyΓ βmalΓ nhwlΙΜnvlΙΜ tΙΜ βbenΙΙ βtΙn βΙΓ© ... (+18 more) |
28 |
| 64k | βkoffi βdanger , βΙΜ βnyΓ βmalΓ nhwlΙΜnvlΙΜ tΙΜ βbenΙΙ βtΙn βΙΓ© ... (+18 more) |
28 |
Sample 2: Kuwanwangu nyi glekΙxwe Ιokpo nΗ tokpΙnlavi Kwaba tΙn nΓΊ tokpΙnla Natitingu tΙn ...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βku wan wan gu βnyi βglekΙxwe βΙokpo βnΗ βtokpΙnlavi βkwaba ... (+12 more) |
22 |
| 16k | βkuwanwangu βnyi βglekΙxwe βΙokpo βnΗ βtokpΙnlavi βkwaba βtΙn βnΓΊ βtokpΙnla ... (+9 more) |
19 |
| 32k | βkuwanwangu βnyi βglekΙxwe βΙokpo βnΗ βtokpΙnlavi βkwaba βtΙn βnΓΊ βtokpΙnla ... (+9 more) |
19 |
| 64k | βkuwanwangu βnyi βglekΙxwe βΙokpo βnΗ βtokpΙnlavi βkwaba βtΙn βnΓΊ βtokpΙnla ... (+9 more) |
19 |
Sample 3: Ablu Ι hwenu e minyΙΜ alo weziza han Ι wΙ nΙ nyi mΙΜ. Xixa tΙn
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βab lu βΙ βhwenu βe βmin yΙΜ βalo βweziza βhan ... (+8 more) |
18 |
| 16k | βablu βΙ βhwenu βe βminyΙΜ βalo βweziza βhan βΙ βwΙ ... (+6 more) |
16 |
| 32k | βablu βΙ βhwenu βe βminyΙΜ βalo βweziza βhan βΙ βwΙ ... (+6 more) |
16 |
| 64k | βablu βΙ βhwenu βe βminyΙΜ βalo βweziza βhan βΙ βwΙ ... (+6 more) |
16 |
Key Findings
- Best Compression: 64k achieves 4.124x compression
- Lowest UNK Rate: 8k with 0.1627% 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 | 1,671 | 10.71 | 7,538 | 38.1% | 71.7% |
| 2-gram | Subword | 265 π | 8.05 | 2,254 | 68.9% | 98.7% |
| 3-gram | Word | 2,808 | 11.46 | 12,455 | 33.4% | 62.3% |
| 3-gram | Subword | 1,585 | 10.63 | 14,789 | 35.7% | 77.3% |
| 4-gram | Word | 3,755 | 11.87 | 19,739 | 32.3% | 58.3% |
| 4-gram | Subword | 5,749 | 12.49 | 55,463 | 22.8% | 55.5% |
| 5-gram | Word | 2,983 | 11.54 | 15,474 | 34.1% | 61.1% |
| 5-gram | Subword | 12,261 | 13.58 | 96,928 | 17.0% | 44.8% |
Top 5 N-grams by Size
2-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | tΙn mΙ |
7,028 |
| 2 | mΙ Ιo |
3,347 |
| 3 | tΙn lΙ |
2,790 |
| 4 | mΙ e |
2,133 |
| 5 | dodo tΙn |
1,886 |
3-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | tΙn mΙ Ιo |
2,782 |
| 2 | jΓ¬ Γ© ΙΔΓ¨ |
1,274 |
| 3 | ayi e jì |
1,171 |
| 4 | tΙn mΙ Γ© |
1,170 |
| 5 | e jì é |
1,168 |
4-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | ayi e jì é |
1,167 |
| 2 | e jΓ¬ Γ© ΙΔΓ¨ |
1,157 |
| 3 | e ΙΔΓ¨ mΙ e |
1,134 |
| 4 | gbΙtΙ e ΙΔΓ¨ mΙ |
1,133 |
| 5 | tΙn mΙ Ιo benΙ |
1,090 |
5-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | ayi e jΓ¬ Γ© ΙΔΓ¨ |
1,156 |
| 2 | gbΙtΙ e ΙΔΓ¨ mΙ e |
1,133 |
| 3 | benΙ ayi e jΓ¬ Γ© |
1,064 |
| 4 | Ιo benΙ ayi e jΓ¬ |
1,060 |
| 5 | mΙ Ιo benΙ ayi e |
1,060 |
2-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | n _ |
58,568 |
| 2 | o _ |
46,161 |
| 3 | _ t |
45,106 |
| 4 | Ι n |
41,894 |
| 5 | _ Ι |
36,979 |
3-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | Ι n _ |
27,349 |
| 2 | t Ι n |
25,832 |
| 3 | _ t Ι |
24,140 |
| 4 | _ Ι o |
19,620 |
| 5 | Ι o _ |
17,028 |
4-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ t Ι n |
23,518 |
| 2 | t Ι n _ |
22,408 |
| 3 | _ Ι o _ |
16,782 |
| 4 | _ m Ι _ |
10,812 |
| 5 | k p Ι n |
8,817 |
5-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ t Ι n _ |
20,896 |
| 2 | _ t o k p |
8,408 |
| 3 | t o k p Ι |
8,400 |
| 4 | o k p Ι n |
8,400 |
| 5 | t Ι n _ m |
7,246 |
Key Findings
- Best Perplexity: 2-gram (subword) with 265
- Entropy Trend: Decreases with larger n-grams (more predictable)
- Coverage: Top-1000 patterns cover ~45% 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 | 0.7272 | 1.655 | 4.51 | 24,791 | 27.3% |
| 1 | Subword | 1.2806 | 2.429 | 14.66 | 265 | 0.0% |
| 2 | Word | 0.2756 | 1.210 | 1.70 | 111,357 | 72.4% |
| 2 | Subword | 1.1501 | 2.219 | 7.00 | 3,884 | 0.0% |
| 3 | Word | 0.1152 | 1.083 | 1.21 | 188,520 | 88.5% |
| 3 | Subword | 0.7806 | 1.718 | 3.61 | 27,160 | 21.9% |
| 4 | Word | 0.0471 π | 1.033 | 1.08 | 227,466 | 95.3% |
| 4 | Subword | 0.5178 | 1.432 | 2.22 | 98,034 | 48.2% |
Generated Text Samples (Word-based)
Below are text samples generated from each word-based Markov chain model:
Context Size 1:
tΙn mΙ wli hwe Ι huzu tokpΙnlavi agΙnkanmΙ tΙn bo ΙyΙ Ι ylΙ Ι Ιo yovogbΓ¨Ιo tokpΙn alibori e nΙΜ kpΓ©nukΓΊn tovixixa wΗ Γ© kpo hΙnnu mΙ bo nΙ nyΓ¬ doe Ιo lΓ© e Γ© mΙ xwΓ©do 1 lΙ nukΙnnΙtΙ hwΙxo tΙn ayi e yovo hwan
Context Size 2:
tΙn mΙ ΙΓ² totaligbΓ© gbadahweji benΙΙtΓ² tΙn lΙ mi na mΙ xogbΓ¨ to Ι tΙn Ιo tantΙnmΙ Ιo benΙ ayi e jΓ¬ Γ© ΙΔΓ¨ lΔΓ¨ akpΙkpΙ ΙΓ© Ιe Ι Γ¨ sΙ Ι ΙΙmΙnumΙ e lΙΜzun gletoxo do sΙΜnxwΔ jΓ sin azan ayizin 6 xwejisΓΉn lΓ©xwΓ© tΙn mΙ toxoΙΙgbΙ tΙn
Context Size 3:
tΙn mΙ Ιo atacora e lΙΜ nyi gletoxo do sΙΜnxwΔ jΓ sin azan ayizin 6 xwejisΓΉn lΓ© xwΓ©lΓ©jΓ¬ Γ© ΙΔΓ¨ zinvie Ιo tokpΙnlavi zinviΓ© tΙn mΙ Ιo benΙΙto mΙ bo nyi sΙmi sΙmi ΙΙΜmΙnu lΙayi e jΓ¬ Γ© ΙΔΓ¨ tokpΙnlΓ‘vΓ¬ tayaku tΙn Ι nyi tokpΙnlavi Ιokpo Ιo wΓ² 10 Δ Ιo tokpΙnla
Context Size 4:
ayi e jΓ¬ Γ© ΙΔΓ¨ dovogon Ιo tokpΙnlavi zogbodomey tΙn mΙ Ιo zou e lΙΜ nyΓ gletoxo ΙΓ² sΙΜnxwΓe jΓ¬ Γ© ΙΔΓ¨ bouhanrou Ιo tokpΙnlavi gomparou tΙn mΙ Ιo alibori e lΙΜ nyi gletoxo Ιo sΙΜnxwΔ jΓe ΙΔΓ¨ mΙ e axΙsuxwe insae instad e nΙΜn kpΓ© nunkΓΊn tovixixa wΗ Γ© lΙn xΙta 248 nΗ gbΙtΙ
Generated Text Samples (Subword-based)
Below are text samples generated from each subword-based Markov chain model:
Context Size 1:
_be,._Ιo_ΙΔΓ¨_e"_nΙn_kuΙoudoku_too_Γ©_mbe_gblΙn_ΙΓ²
Context Size 2:
n_kan)_xΙtan_Γ¨_Ιoo_tΙnla_akanΙie_Ι_tokpΓ©_dodo_tΙntr
Context Size 3:
Ιn_atlant_dolore_ttΙn_ΙΓ³_azinkpo_Ι,__tΙn_Ι_tΙn_lΓ©xwΓ©_d
Context Size 4:
_tΙn._Ιo_tokpΙn_atutΙn_lΙ_sin_azΗn_20Ι_Ιo_tokpΙnlavi_tΙn,
Key Findings
- Best Predictability: Context-4 (word) with 95.3% predictability
- Branching Factor: Decreases with context size (more deterministic)
- Memory Trade-off: Larger contexts require more storage (98,034 contexts)
- Recommendation: Context-3 or Context-4 for text generation
4. Vocabulary Analysis
Statistics
| Metric | Value |
|---|---|
| Vocabulary Size | 11,148 |
| Total Tokens | 363,048 |
| Mean Frequency | 32.57 |
| Median Frequency | 3 |
| Frequency Std Dev | 405.71 |
Most Common Words
| Rank | Word | Frequency |
|---|---|---|
| 1 | tΙn | 23,451 |
| 2 | Ιo | 16,822 |
| 3 | e | 15,001 |
| 4 | mΙ | 14,011 |
| 5 | Γ© | 10,488 |
| 6 | Ι | 10,251 |
| 7 | lΙ | 8,160 |
| 8 | nyi | 5,259 |
| 9 | nΙ | 5,214 |
| 10 | ΙΓ² | 4,492 |
Least Common Words (from vocabulary)
| Rank | Word | Frequency |
|---|---|---|
| 1 | rust | 2 |
| 2 | gnu | 2 |
| 3 | programme | 2 |
| 4 | java | 2 |
| 5 | api | 2 |
| 6 | columns | 2 |
| 7 | break | 2 |
| 8 | inside | 2 |
| 9 | avoid | 2 |
| 10 | greek | 2 |
Zipf's Law Analysis
| Metric | Value |
|---|---|
| Zipf Coefficient | 1.1833 |
| RΒ² (Goodness of Fit) | 0.993854 |
| Adherence Quality | excellent |
Coverage Analysis
| Top N Words | Coverage |
|---|---|
| Top 100 | 63.7% |
| Top 1,000 | 86.2% |
| Top 5,000 | 95.8% |
| Top 10,000 | 99.4% |
Key Findings
- Zipf Compliance: RΒ²=0.9939 indicates excellent adherence to Zipf's law
- High Frequency Dominance: Top 100 words cover 63.7% of corpus
- Long Tail: 1,148 words needed for remaining 0.6% 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 | 0.6254 π | 0.3950 | N/A | N/A |
| mono_64d | 64 | 0.3309 | 0.3691 | N/A | N/A |
| mono_128d | 128 | 0.0582 | 0.3829 | N/A | N/A |
| aligned_32d | 32 | 0.6254 | 0.3991 | 0.0100 | 0.1180 |
| aligned_64d | 64 | 0.3309 | 0.3687 | 0.0300 | 0.1420 |
| aligned_128d | 128 | 0.0582 | 0.3777 | 0.0520 | 0.2300 |
Key Findings
- Best Isotropy: mono_32d with 0.6254 (more uniform distribution)
- Semantic Density: Average pairwise similarity of 0.3821. Lower values indicate better semantic separation.
- Alignment Quality: Aligned models achieve up to 5.2% 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 | 0.364 | 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 |
|---|
Productive Suffixes
| Suffix | Examples |
|---|---|
-mΙ |
akwΙnyanumΙ, mimΙ, wΓΉnmΙ |
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 |
|---|---|---|---|
okpo |
1.55x | 21 contexts | xokpo, yokpo, lokpo |
Ιokp |
1.57x | 16 contexts | ΙokpΙ, ΙokpΓ², ΙokpΓ³ |
Ιnyi |
1.72x | 12 contexts | sΙnyi, lΙnyiji, ΙΙnyitΙ |
plΙn |
1.72x | 12 contexts | kplΙn, kplΙnnΗ, kplΙnyi |
mΙnu |
1.74x | 10 contexts | dΙmΙnu, wemΙnu, ΙΙmΙnu |
ntΙn |
1.41x | 16 contexts | tantΙn, tΗntΙn, xΙntΙn |
ligb |
1.67x | 9 contexts | aligbo, taligbΓ©, taligbe |
pΙnl |
1.58x | 10 contexts | kpΙnla, tokpΙnlΓ‘, tΓ²kpΙnlΓ |
hwen |
1.42x | 13 contexts | hwenΓΉ, hwenu, hwenΓΊ |
igbe |
1.53x | 10 contexts | jigbe, yigbe, igbere |
ukun |
1.53x | 9 contexts | wukun, nukun, bukunbΓ© |
tokp |
1.59x | 8 contexts | tokpn, tokpo, tokpa |
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.
No significant affix co-occurrences detected.
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 |
|---|---|---|---|
| liberiatΓ²mΙ | liberiatΓ²-mΙ |
4.5 | liberiatΓ² |
| gabΙntomΙ | gabΙnto-mΙ |
4.5 | gabΙnto |
| jΙwunjΙjamΙ | jΙwunjΙja-mΙ |
4.5 | jΙwunjΙja |
| flansΓ©gbΓ¨mΙ | flansΓ©gbΓ¨-mΙ |
4.5 | flanségbè |
| kplekplemΙ | kplekple-mΙ |
4.5 | kplekple |
| flansΓ©gbΓ©mΙ | flansΓ©gbΓ©-mΙ |
4.5 | flansΓ©gbΓ© |
| senegaltΓ²mΙ | senegaltΓ²-mΙ |
4.5 | senegaltΓ² |
| flansetomΙ | flanseto-mΙ |
4.5 | flanseto |
| kplΓ©kplΓ©mΙ | kplΓ©kplΓ©-mΙ |
4.5 | kplΓ©kplΓ© |
| avΙΙesinukunmΙ | avΙΙesinukun-mΙ |
1.5 | avΙΙesinukun |
| zogbodomΙ | zogbodo-mΙ |
1.5 | zogbodo |
| nΓΉkplΙnmΙ | nΓΉkplΙn-mΙ |
1.5 | nΓΉkplΙn |
| kotoklomΙ | kotoklo-mΙ |
1.5 | kotoklo |
| adakplamΙ | adakpla-mΙ |
1.5 | adakpla |
| azΙnzunmΙ | azΙnzun-mΙ |
1.5 | azΙnzun |
6.6 Linguistic Interpretation
Automated Insight: The language Fon 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.
7. Summary & Recommendations
Production Recommendations
| Component | Recommended | Rationale |
|---|---|---|
| Tokenizer | 64k BPE | Best compression (4.12x) |
| N-gram | 2-gram | Lowest perplexity (265) |
| Markov | Context-4 | Highest predictability (95.3%) |
| 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: 2026-01-04 14:47:03



















