Xhosa - Wikilangs Models
Comprehensive Research Report & Full Ablation Study
This repository contains NLP models trained and evaluated by Wikilangs, specifically on Xhosa 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 | 3.679x | 3.68 | 0.2207% | 429,593 |
| 16k | 4.111x | 4.11 | 0.2466% | 384,442 |
| 32k | 4.548x | 4.55 | 0.2728% | 347,524 |
| 64k | 4.929x π | 4.93 | 0.2956% | 320,656 |
Tokenization Examples
Below are sample sentences tokenized with each vocabulary size:
Sample 1: I-Orta Nova (kude kube ebizwa ngokuba yi-Orta) ngumasipala wase-Italiya onabemi ...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βi - or ta βnova β( kude βkube βebizwa βngokuba ... (+16 more) |
26 |
| 16k | βi - or ta βnova β( kude βkube βebizwa βngokuba ... (+15 more) |
25 |
| 32k | βi - orta βnova β( kude βkube βebizwa βngokuba βyi ... (+13 more) |
23 |
| 64k | βi - orta βnova β( kude βkube βebizwa βngokuba βyi ... (+13 more) |
23 |
Sample 2: Icawa yindawo yokuhlanganisana yamaKristu, nokuba angamaKatolika, amaOthodoki ok...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βicawa βyindawo βyoku hlang ani sana βyama kristu , βnokuba ... (+13 more) |
23 |
| 16k | βicawa βyindawo βyoku hlangani sana βyama kristu , βnokuba βangama ... (+11 more) |
21 |
| 32k | βicawa βyindawo βyoku hlanganisana βyamakristu , βnokuba βangama katolika , ... (+5 more) |
15 |
| 64k | βicawa βyindawo βyoku hlanganisana βyamakristu , βnokuba βangama katolika , ... (+3 more) |
13 |
Sample 3: IDaouche yilali kunye nendawo yasemaphandleni eNiger. Ukusukela ibinabemi Iimbek...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βida o u che βyilali βkunye βnendawo βyasemaphandleni βeniger . ... (+6 more) |
16 |
| 16k | βida o u che βyilali βkunye βnendawo βyasemaphandleni βeniger . ... (+4 more) |
14 |
| 32k | βida ouche βyilali βkunye βnendawo βyasemaphandleni βeniger . βukusukela βibinabemi ... (+2 more) |
12 |
| 64k | βidaouche βyilali βkunye βnendawo βyasemaphandleni βeniger . βukusukela βibinabemi βiimbekiselo ... (+1 more) |
11 |
Key Findings
- Best Compression: 64k achieves 4.929x compression
- Lowest UNK Rate: 8k with 0.2207% 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 | 3,253 | 11.67 | 5,073 | 16.6% | 52.9% |
| 2-gram | Subword | 259 π | 8.02 | 2,144 | 68.4% | 99.5% |
| 3-gram | Word | 3,451 | 11.75 | 5,094 | 16.6% | 50.4% |
| 3-gram | Subword | 2,203 | 11.11 | 15,967 | 24.4% | 72.7% |
| 4-gram | Word | 9,133 | 13.16 | 12,576 | 11.1% | 29.3% |
| 4-gram | Subword | 12,328 | 13.59 | 78,348 | 10.9% | 38.3% |
| 5-gram | Word | 7,660 | 12.90 | 10,427 | 12.5% | 30.1% |
| 5-gram | Subword | 39,954 | 15.29 | 185,127 | 6.4% | 23.0% |
Top 5 N-grams by Size
2-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | kunye ne |
613 |
| 2 | emzantsi afrika |
405 |
| 3 | of the |
341 |
| 4 | ngokuba yi |
328 |
| 5 | emva koko |
192 |
3-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | iimbekiselo amakhonkco angaphandle |
97 |
| 2 | c eyona nyanga |
78 |
| 3 | cc by post |
76 |
| 4 | org cc by |
76 |
| 5 | sa geonames org |
76 |
4-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | sa geonames org cc |
76 |
| 2 | org cc by post |
76 |
| 3 | geonames org cc by |
76 |
| 4 | updated database download sa |
76 |
| 5 | post updated database download |
76 |
5-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | sa geonames org cc by |
76 |
| 2 | org cc by post updated |
76 |
| 3 | cc by post updated database |
76 |
| 4 | by post updated database download |
76 |
| 5 | post updated database download sa |
76 |
2-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | a _ |
100,386 |
| 2 | e _ |
62,380 |
| 3 | a n |
57,095 |
| 4 | o _ |
53,048 |
| 5 | n g |
49,243 |
3-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | l a _ |
21,271 |
| 2 | _ n g |
19,972 |
| 3 | _ k w |
17,850 |
| 4 | _ k u |
17,761 |
| 5 | a _ k |
15,793 |
4-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | n y e _ |
11,326 |
| 2 | e l a _ |
8,721 |
| 3 | _ u k u |
8,570 |
| 4 | a _ n g |
8,421 |
| 5 | _ n g o |
8,259 |
5-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | k u b a _ |
5,628 |
| 2 | u n y e _ |
5,544 |
| 3 | k u n y e |
5,475 |
| 4 | n y e _ n |
5,432 |
| 5 | _ k u n y |
5,381 |
Key Findings
- Best Perplexity: 2-gram (subword) with 259
- Entropy Trend: Decreases with larger n-grams (more predictable)
- Coverage: Top-1000 patterns cover ~23% 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 | 0.6070 | 1.523 | 3.17 | 104,417 | 39.3% |
| 1 | Subword | 1.1180 | 2.171 | 9.35 | 521 | 0.0% |
| 2 | Word | 0.1066 | 1.077 | 1.18 | 329,356 | 89.3% |
| 2 | Subword | 1.0676 | 2.096 | 6.29 | 4,869 | 0.0% |
| 3 | Word | 0.0246 | 1.017 | 1.03 | 387,463 | 97.5% |
| 3 | Subword | 0.9182 | 1.890 | 4.35 | 30,613 | 8.2% |
| 4 | Word | 0.0088 π | 1.006 | 1.01 | 398,295 | 99.1% |
| 4 | Subword | 0.7004 | 1.625 | 2.83 | 133,109 | 30.0% |
Generated Text Samples (Word-based)
Below are text samples generated from each word-based Markov chain model:
Context Size 1:
i multibit ye analog computer ngomzila wefowuni kuquka i eccentric kwaye iza wamkele ukristu bc nang...kunye newololo music education act isikolo samagriqua phesheya kwenciba nakumaxesha angaphambili kun...kwaye inomsebenzi wokutyumba oosompempe ukuba bamthabathe ngokwegqwirha elikhwela esinga ejongise ng...
Context Size 2:
kunye ne 8 500 bc ngexesha lestone age ukuya ekupheleni kwekhulu le 19 pos iqela pld wof the bhacas from earliest times to doctoral dissertation university of natal after he bought a sto...ngokuba yi alchemy nangona kunjalo waqhubeka wasebenza kuguqulo lwendumasiso lwenoveli yodidi engumz...
Context Size 3:
iimbekiselo amakhonkco angaphandle indawo esemthethweni ngesiphuthukezi baseroraimac eyona nyanga ishushu ngujulayi nge c kwaye eyona ngqele kafebruwari ngo c umyinge wokuna kwemvula ...cc by post updated database download sa ime kumasipala wasekalix kommun kunye nephondo lasenorbotten...
Context Size 4:
by post updated database download sa ifumaneka kwiphondo leprovincia di foggia kunye nommandla wepug...sa geonames org cc by post updated database download sa ifumaneka kummandla wezoqoqosho weylΓ€ savo k...cc by post updated database download sa ifumaneka kwiphondo leprovincia di verona kunye nommandla we...
Generated Text Samples (Subword-based)
Below are text samples generated from each subword-based Markov chain model:
Context Size 1:
_ku_nazo_eayβuthabekwhut_(yose_:esisi_jekwabamba
Context Size 2:
a_es._kwagom_hayse_ngozabonfer,_icano_yelo_ye_ic_ek
Context Size 3:
la_wenziswengokwen_ngoxa_popolophu.__kwimi_eli_uba_uku
Context Size 4:
nye_la_confederano,ela_lwaseshumi_amaq_ukuze_sifumandeley
Key Findings
- Best Predictability: Context-4 (word) with 99.1% predictability
- Branching Factor: Decreases with context size (more deterministic)
- Memory Trade-off: Larger contexts require more storage (133,109 contexts)
- Recommendation: Context-3 or Context-4 for text generation
4. Vocabulary Analysis
Statistics
| Metric | Value |
|---|---|
| Vocabulary Size | 35,909 |
| Total Tokens | 362,403 |
| Mean Frequency | 10.09 |
| Median Frequency | 3 |
| Frequency Std Dev | 60.47 |
Most Common Words
| Rank | Word | Frequency |
|---|---|---|
| 1 | i | 5,328 |
| 2 | kunye | 5,290 |
| 3 | kwaye | 2,522 |
| 4 | ukuba | 2,013 |
| 5 | okanye | 1,987 |
| 6 | 1 | 1,832 |
| 7 | the | 1,804 |
| 8 | of | 1,523 |
| 9 | kwi | 1,513 |
| 10 | ke | 1,364 |
Least Common Words (from vocabulary)
| Rank | Word | Frequency |
|---|---|---|
| 1 | okuthengiswa | 2 |
| 2 | esitalatweni | 2 |
| 3 | ezitalatweni | 2 |
| 4 | kwesitalato | 2 |
| 5 | pilibhit | 2 |
| 6 | ezifundo | 2 |
| 7 | nenkubazeko | 2 |
| 8 | yaseluthere | 2 |
| 9 | ceulji | 2 |
| 10 | kwesport | 2 |
Zipf's Law Analysis
| Metric | Value |
|---|---|
| Zipf Coefficient | 0.8870 |
| RΒ² (Goodness of Fit) | 0.995256 |
| Adherence Quality | excellent |
Coverage Analysis
| Top N Words | Coverage |
|---|---|
| Top 100 | 21.1% |
| Top 1,000 | 46.3% |
| Top 5,000 | 69.4% |
| Top 10,000 | 80.1% |
Key Findings
- Zipf Compliance: RΒ²=0.9953 indicates excellent adherence to Zipf's law
- High Frequency Dominance: Top 100 words cover 21.1% of corpus
- Long Tail: 25,909 words needed for remaining 19.9% 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 | 0.8914 | 0.2946 | N/A | N/A |
| mono_64d | 64 | 0.6652 | 0.2434 | N/A | N/A |
| mono_128d | 128 | 0.1559 | 0.2440 | N/A | N/A |
| aligned_32d | 32 | 0.8914 π | 0.2952 | 0.0360 | 0.2160 |
| aligned_64d | 64 | 0.6652 | 0.2484 | 0.0540 | 0.2700 |
| aligned_128d | 128 | 0.1559 | 0.2308 | 0.0880 | 0.3480 |
Key Findings
- Best Isotropy: aligned_32d with 0.8914 (more uniform distribution)
- Semantic Density: Average pairwise similarity of 0.2594. Lower values indicate better semantic separation.
- Alignment Quality: Aligned models achieve up to 8.8% 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 | 0.310 | 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 |
|---|---|
-i |
inyongo, itshintshile, iimitha |
-e |
ehleli, elected, esebenzayo |
-u |
umbane, umtu, ubunkokeli |
-a |
abathunywa, amabanga, arlington |
-n |
ngowayesakuba, njengeempawu, netherland |
-ne |
netherland, neutron, nelungelo |
-s |
steatorrhea, scored, sant |
-ku |
kubanjelwa, kunokwenzeka, kusenziwa |
Productive Suffixes
| Suffix | Examples |
|---|---|
-a |
lokubhala, ngowayesakuba, wamaza |
-o |
inyongo, ngenyawo, kwintetho |
-i |
yabancinci, ngeentombi, ehleli |
-e |
itshintshile, glucose, umbane |
-la |
lokubhala, elivuselela, bawela |
-wa |
kubanjelwa, abathunywa, kwaqhutywa |
-ni |
ekujonganeni, empumelelweni, udlamini |
-yo |
esebenzayo, ukwaziyo, elichaseneyo |
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 |
|---|---|---|---|
khul |
2.03x | 88 contexts | khulu, akhule, ekhula |
enzi |
2.13x | 60 contexts | menzi, enzima, enziwa |
heth |
2.04x | 68 contexts | khetha, khetho, utheth |
aban |
1.89x | 70 contexts | abane, abanye, abanga |
okub |
1.86x | 55 contexts | okuba, nokuba, sokuba |
ezin |
1.88x | 52 contexts | ezine, ezinde, ezinee |
ants |
2.26x | 23 contexts | gantsa, nantso, plants |
andl |
1.90x | 41 contexts | mandla, sandla, imandla |
ngen |
1.58x | 82 contexts | ingene, ongena, angena |
ndle |
1.83x | 41 contexts | endle, bundle, ndlebe |
hulu |
1.94x | 32 contexts | khulu, akhulu, ikhulu |
bant |
2.19x | 21 contexts | bantu, abantu, ubantu |
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 |
|---|---|---|---|
-n |
-a |
291 words | njengomasipala, nechina |
-u |
-a |
256 words | ukuchazwa, unobhala |
-n |
-o |
226 words | nkonzo, nenkathalo |
-e |
-a |
216 words | ephesheya, entshwana |
-i |
-a |
203 words | ingenziwa, ingena |
-n |
-i |
179 words | ngamagqabi, neegesi |
-e |
-o |
171 words | ebamako, ezichaphazelekayo |
-i |
-o |
156 words | isibonelelo, ibibalihlazo |
-k |
-a |
156 words | kuyakweza, kuyafana |
-l |
-a |
153 words | lwama, litsha |
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 |
|---|---|---|---|
| kamkhwebane | kamkhweb-a-ne |
7.5 | a |
| yasentaliyane | yasentaliy-a-ne |
7.5 | a |
| ubungcali | ubungc-a-li |
7.5 | a |
| kwiitshaneli | kw-i-itshaneli |
7.5 | itshaneli |
| nesijamani | nesijam-a-ni |
7.5 | a |
| ezingabamelwane | ezingabamelw-a-ne |
7.5 | a |
| uyavakala | uyavak-a-la |
7.5 | a |
| abafikayo | abafik-a-yo |
7.5 | a |
| nokudodobala | nokudodob-a-la |
7.5 | a |
| kwisigwebo | kwisig-we-bo |
7.5 | we |
| ezimfutshane | ezimfutsh-a-ne |
7.5 | a |
| uzbekistan | uzbekist-a-n |
7.5 | a |
| kwiinkulungwane | kwiinkulungw-a-ne |
7.5 | a |
| sebastian | sebasti-a-n |
7.5 | a |
| ovuthuzayo | ovuthuz-a-yo |
7.5 | a |
6.6 Linguistic Interpretation
Automated Insight: The language Xhosa 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 (4.93x) |
| N-gram | 2-gram | Lowest perplexity (259) |
| Markov | Context-4 | Highest predictability (99.1%) |
| 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: 2026-01-11 04:59:25



















