language: st
language_name: Southern Sotho
language_family: bantu_southern
tags:
- wikilangs
- nlp
- tokenizer
- embeddings
- n-gram
- markov
- wikipedia
- feature-extraction
- sentence-similarity
- tokenization
- n-grams
- markov-chain
- text-mining
- fasttext
- babelvec
- vocabulous
- vocabulary
- monolingual
- family-bantu_southern
license: mit
library_name: wikilangs
pipeline_tag: text-generation
datasets:
- omarkamali/wikipedia-monthly
dataset_info:
name: wikipedia-monthly
description: Monthly snapshots of Wikipedia articles across 300+ languages
metrics:
- name: best_compression_ratio
type: compression
value: 4.418
- name: best_isotropy
type: isotropy
value: 0.5673
- name: vocabulary_size
type: vocab
value: 0
generated: 2026-01-10T00:00:00.000Z
Southern Sotho - Wikilangs Models
Comprehensive Research Report & Full Ablation Study
This repository contains NLP models trained and evaluated by Wikilangs, specifically on Southern Sotho Wikipedia data. We analyze tokenizers, n-gram models, Markov chains, vocabulary statistics, and word embeddings.
📋 Repository Contents
Models & Assets
- Tokenizers (8k, 16k, 32k, 64k)
- N-gram models (2, 3, 4, 5-gram)
- Markov chains (context of 1, 2, 3, 4 and 5)
- Subword N-gram and Markov chains
- Embeddings in various sizes and dimensions (aligned and unaligned)
- Language Vocabulary
- Language Statistics
Analysis and Evaluation
- 1. Tokenizer Evaluation
- 2. N-gram Model Evaluation
- 3. Markov Chain Evaluation
- 4. Vocabulary Analysis
- 5. Word Embeddings Evaluation
- 6. Morphological Analysis (Experimental)
- 7. Summary & Recommendations
- Metrics Glossary
- Visualizations Index
1. Tokenizer Evaluation
Results
| Vocab Size | Compression | Avg Token Len | UNK Rate | Total Tokens |
|---|---|---|---|---|
| 8k | 3.776x | 3.78 | 0.2714% | 231,037 |
| 16k | 4.068x | 4.07 | 0.2923% | 214,484 |
| 32k | 4.296x | 4.30 | 0.3087% | 203,079 |
| 64k | 4.418x 🏆 | 4.42 | 0.3175% | 197,468 |
Tokenization Examples
Below are sample sentences tokenized with each vocabulary size:
Sample 1: Siphelele Mthembu (ya hlahileng ka la 15 Phato ke sebapadi sa bolo ya maoto Afri...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | ▁si phe lele ▁mthe mbu ▁( ya ▁hlahileng ▁ka ▁la ... (+24 more) |
34 |
| 16k | ▁siphelele ▁mthembu ▁( ya ▁hlahileng ▁ka ▁la ▁ 1 5 ... (+21 more) |
31 |
| 32k | ▁siphelele ▁mthembu ▁( ya ▁hlahileng ▁ka ▁la ▁ 1 5 ... (+21 more) |
31 |
| 64k | ▁siphelele ▁mthembu ▁( ya ▁hlahileng ▁ka ▁la ▁ 1 5 ... (+21 more) |
31 |
Sample 2: Rafael José Orozco Maestre (Hlakubele 24, – 11 Phupu ne e le sebini, sengoli sa ...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | ▁ra fa el ▁jo s é ▁o ro z co ... (+26 more) |
36 |
| 16k | ▁rafa el ▁josé ▁oroz co ▁mae st re ▁( hla ... (+21 more) |
31 |
| 32k | ▁rafael ▁josé ▁orozco ▁mae st re ▁( hlakubele ▁ 2 ... (+18 more) |
28 |
| 64k | ▁rafael ▁josé ▁orozco ▁maestre ▁( hlakubele ▁ 2 4 , ... (+16 more) |
26 |
Sample 3: Mokwallo ke lekeishene le haufi le Vredefort, ka hare ho Masepala wa Ngwathe, po...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | ▁mo kwa llo ▁ke ▁lekeishene ▁le ▁haufi ▁le ▁vrede fort ... (+17 more) |
27 |
| 16k | ▁mo kwa llo ▁ke ▁lekeishene ▁le ▁haufi ▁le ▁vredefort , ... (+16 more) |
26 |
| 32k | ▁mokwallo ▁ke ▁lekeishene ▁le ▁haufi ▁le ▁vredefort , ▁ka ▁hare ... (+14 more) |
24 |
| 64k | ▁mokwallo ▁ke ▁lekeishene ▁le ▁haufi ▁le ▁vredefort , ▁ka ▁hare ... (+14 more) |
24 |
Key Findings
- Best Compression: 64k achieves 4.418x compression
- Lowest UNK Rate: 8k with 0.2714% 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 | 4,147 | 12.02 | 10,524 | 21.0% | 52.2% |
| 2-gram | Subword | 184 🏆 | 7.52 | 1,683 | 77.1% | 99.6% |
| 3-gram | Word | 6,664 | 12.70 | 14,321 | 16.6% | 41.7% |
| 3-gram | Subword | 1,318 | 10.36 | 12,094 | 38.3% | 80.9% |
| 4-gram | Word | 13,698 | 13.74 | 22,303 | 10.5% | 28.0% |
| 4-gram | Subword | 6,177 | 12.59 | 50,733 | 19.5% | 52.6% |
| 5-gram | Word | 10,291 | 13.33 | 14,770 | 10.4% | 28.8% |
| 5-gram | Subword | 17,540 | 14.10 | 100,714 | 10.4% | 34.7% |
Top 5 N-grams by Size
2-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | e le |
2,604 |
| 2 | ile a |
2,556 |
| 3 | o ile |
2,550 |
| 4 | afrika borwa |
1,822 |
| 5 | ka la |
1,398 |
3-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | o ile a |
2,458 |
| 2 | e ne e |
839 |
| 3 | ne e le |
639 |
| 4 | sa afrika borwa |
459 |
| 5 | e ile ya |
458 |
4-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | e ne e le |
633 |
| 2 | sa bolo ya maoto |
249 |
| 3 | ka o ile a |
216 |
| 4 | bolo ya maoto sa |
212 |
| 5 | ka moka afrika borwa |
179 |
5-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | sa bolo ya maoto sa |
211 |
| 2 | sebapadi sa bolo ya maoto |
161 |
| 3 | bolo ya maoto sa afrika |
156 |
| 4 | ya maoto sa afrika borwa |
155 |
| 5 | ke sebapadi sa bolo ya |
146 |
2-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | a _ |
129,546 |
| 2 | e _ |
80,922 |
| 3 | o _ |
53,695 |
| 4 | l e |
48,470 |
| 5 | _ l |
37,957 |
3-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | l e _ |
26,748 |
| 2 | _ l e |
23,579 |
| 3 | n g _ |
22,710 |
| 4 | k a _ |
18,228 |
| 5 | h o _ |
18,075 |
4-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ l e _ |
15,451 |
| 2 | _ h o _ |
13,673 |
| 3 | _ k a _ |
12,473 |
| 4 | e n g _ |
11,083 |
| 5 | _ y a _ |
9,749 |
5-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | a _ h o _ |
6,521 |
| 2 | _ t s a _ |
5,552 |
| 3 | _ t s e _ |
4,528 |
| 4 | e _ l e _ |
4,398 |
| 5 | a _ l e _ |
4,221 |
Key Findings
- Best Perplexity: 2-gram (subword) with 184
- Entropy Trend: Decreases with larger n-grams (more predictable)
- Coverage: Top-1000 patterns cover ~35% 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 | 0.7915 | 1.731 | 4.86 | 30,896 | 20.8% |
| 1 | Subword | 0.9659 | 1.953 | 8.17 | 449 | 3.4% |
| 2 | Word | 0.3145 | 1.244 | 1.77 | 149,534 | 68.5% |
| 2 | Subword | 1.0583 | 2.082 | 6.21 | 3,664 | 0.0% |
| 3 | Word | 0.1184 | 1.086 | 1.22 | 264,209 | 88.2% |
| 3 | Subword | 0.8464 | 1.798 | 3.86 | 22,722 | 15.4% |
| 4 | Word | 0.0501 🏆 | 1.035 | 1.08 | 320,187 | 95.0% |
| 4 | Subword | 0.5799 | 1.495 | 2.42 | 87,601 | 42.0% |
Generated Text Samples (Word-based)
Below are text samples generated from each word-based Markov chain model:
Context Size 1:
le ka setereke provensing ya hae pele a le phahameng sa setjhaba ba hae la sebakae neng se bapalang e nang le lefapha lefapha bakeng sa bohareng sa boeta pele aho masepala wa bophelo lisebelisoa tsohle tse ling tsa zone 14 qetellong ya latela mokhatlo o
Context Size 2:
e le puo yaa bahatelli e le toropo ea ypres setsi sa setso sa sekgowaile a fumana diploma ya hae le ka leboya ho noka ya elands ka histori sebaka senao ile a khethwa sehlopheng sa gauteng afrika borwa u23 ha a hopola mabaka a mang a
Context Size 3:
o ile a latelwa ke moprofesa daya reddy ka la 13 phuptjane ke senokwane sa afrika borwa dipinae ne e le ya hae ya independence day dipina bahale ba hosane ho hong ho maafrika borwane e le karolo ea sehlopha se neng se nahana hore se utlwa likhohlano tsa lelapa le ho
Context Size 4:
e ne e le moruti mme seo sa etsa hore a be le maqhama hodima dijo le meetlo letsatsingsa bolo ya maoto sa afrika borwa se bapalang e le sebapadi sa bohareng ba sehlopha sa ts galaxyka o ile a hlaha nakong ea papali ea papadi eo afrika borwa e ileng ya e ba ngaka
Generated Text Samples (Subword-based)
Below are text samples generated from each subword-based Markov chain model:
Context Size 1:
_sts'erie_pa_phaa_lesora_me._ya_ent_afumapa_kabi
Context Size 2:
a_tliaha_ka_bo_o_e_mohlo,_tlo_b_'mo_kemini_wa_mang_
Context Size 3:
le_swa_bokgatang_e_le_mabotjoalonyanng_ba_yuniteremira
Context Size 4:
_le_45_000_ka_e_mpe_ho_bua_kang_jwalo__ka_nation_boydelli
Key Findings
- Best Predictability: Context-4 (word) with 95.0% predictability
- Branching Factor: Decreases with context size (more deterministic)
- Memory Trade-off: Larger contexts require more storage (87,601 contexts)
- Recommendation: Context-3 or Context-4 for text generation
4. Vocabulary Analysis
Statistics
| Metric | Value |
|---|---|
| Vocabulary Size | 14,659 |
| Total Tokens | 368,067 |
| Mean Frequency | 25.11 |
| Median Frequency | 4 |
| Frequency Std Dev | 312.16 |
Most Common Words
| Rank | Word | Frequency |
|---|---|---|
| 1 | le | 15,561 |
| 2 | e | 14,132 |
| 3 | ho | 13,814 |
| 4 | ka | 12,570 |
| 5 | a | 10,894 |
| 6 | ya | 10,066 |
| 7 | ba | 7,883 |
| 8 | sa | 7,305 |
| 9 | o | 6,830 |
| 10 | ea | 5,887 |
Least Common Words (from vocabulary)
| Rank | Word | Frequency |
|---|---|---|
| 1 | baker | 2 |
| 2 | navorsingsentrum | 2 |
| 3 | afrikanerbakens | 2 |
| 4 | federasie | 2 |
| 5 | kultuurvereniginge | 2 |
| 6 | 112 | 2 |
| 7 | ntlokgolo | 2 |
| 8 | lingoli | 2 |
| 9 | moiloa | 2 |
| 10 | trelawny | 2 |
Zipf's Law Analysis
| Metric | Value |
|---|---|
| Zipf Coefficient | 1.1072 |
| R² (Goodness of Fit) | 0.991733 |
| Adherence Quality | excellent |
Coverage Analysis
| Top N Words | Coverage |
|---|---|
| Top 100 | 53.1% |
| Top 1,000 | 76.3% |
| Top 5,000 | 92.1% |
| Top 10,000 | 97.5% |
Key Findings
- Zipf Compliance: R²=0.9917 indicates excellent adherence to Zipf's law
- High Frequency Dominance: Top 100 words cover 53.1% of corpus
- Long Tail: 4,659 words needed for remaining 2.5% 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 | 0.5673 🏆 | 0.3940 | N/A | N/A |
| mono_64d | 64 | 0.1528 | 0.3621 | N/A | N/A |
| mono_128d | 128 | 0.0222 | 0.3760 | N/A | N/A |
| aligned_32d | 32 | 0.5673 | 0.3806 | 0.0140 | 0.2000 |
| aligned_64d | 64 | 0.1528 | 0.3683 | 0.0300 | 0.2140 |
| aligned_128d | 128 | 0.0222 | 0.3775 | 0.0460 | 0.2040 |
Key Findings
- Best Isotropy: mono_32d with 0.5673 (more uniform distribution)
- Semantic Density: Average pairwise similarity of 0.3764. Lower values indicate better semantic separation.
- Alignment Quality: Aligned models achieve up to 4.6% 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 | -0.169 | 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 |
|---|---|
-m |
menyabuketso, motorsports, makhooa |
-ma |
makhooa, maiteko, makhadzi |
-s |
sahesu, sammy, silila |
-b |
blaq, bruce, behile |
-mo |
motorsports, mopalami, motona |
-t |
tlalehilwe, toit, tsebahatsoa |
-bo |
bonahetse, bomampodi, bohahlauli |
-di |
diporesente, dikarabello, dienjini |
Productive Suffixes
| Suffix | Examples |
|---|---|
-ng |
iponahatsang, thahasellang, liking |
-a |
ginwala, elella, makhooa |
-e |
tlalehilwe, ujeqe, vlamertinge |
-g |
iponahatsang, thahasellang, liking |
-o |
menyabuketso, pablo, alebamo |
-i |
giovanni, makhadzi, mopalami |
-s |
motorsports, countries, bioethics |
-n |
in, upington, chan |
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 |
|---|---|---|---|
ilen |
1.60x | 35 contexts | ileng, bileng, nileng |
tswe |
1.62x | 27 contexts | etswe, entswe, tswela |
tsoe |
1.70x | 21 contexts | etsoe, tsoelo, tsoela |
etso |
1.32x | 45 contexts | ketso, setso, etsoa |
tsen |
1.63x | 21 contexts | tsena, etseng, itseng |
lang |
1.46x | 29 contexts | tlang, slang, lange |
elet |
1.45x | 26 contexts | eletsa, leleti, keletso |
bapa |
1.77x | 13 contexts | bapapa, bapale, bapala |
etsi |
1.53x | 17 contexts | wetsi, setsi, metsi |
bets |
1.58x | 15 contexts | betsa, ebetso, sebetse |
otho |
1.41x | 20 contexts | motho, botho, sotho |
ehlo |
1.48x | 14 contexts | lehloyo, lehloeo, lefehlo |
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 |
|---|---|---|---|
-m |
-a |
170 words | maphalla, masilela |
-m |
-i |
128 words | multi, moletsi |
-m |
-e |
128 words | mohurutshe, millione |
-l |
-o |
125 words | lechato, likoloto |
-t |
-g |
120 words | tsejweng, tswelang |
-m |
-o |
120 words | mosiamo, meipiletso |
-t |
-ng |
118 words | tsejweng, tswelang |
-m |
-g |
108 words | maropeng, moelelong |
-b |
-i |
108 words | babuelli, bolepi |
-m |
-ng |
106 words | maropeng, moelelong |
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 |
|---|---|---|---|
| lithaoleng | lithaol-e-ng |
7.5 | e |
| lokolohile | lokoloh-i-le |
7.5 | i |
| hammanskraal | hammanskr-a-al |
7.5 | a |
| phetohelo | phetoh-e-lo |
7.5 | e |
| performing | perform-i-ng |
7.5 | i |
| matšeliso | matše-li-so |
7.5 | li |
| mangaliso | manga-li-so |
7.5 | li |
| tsamaisana | tsamais-a-na |
7.5 | a |
| nathaniel | nathani-e-l |
7.5 | e |
| dihlabeng | dihlab-e-ng |
7.5 | e |
| litlhaselo | litlha-se-lo |
7.5 | se |
| macroalga | macroal-g-a |
7.5 | g |
| hlahisang | hlahi-sa-ng |
7.5 | sa |
| moloisane | moloi-sa-ne |
7.5 | sa |
| batlileng | batli-le-ng |
7.5 | le |
6.6 Linguistic Interpretation
Automated Insight: The language Southern Sotho shows high morphological productivity. The subword models are significantly more efficient than word models, suggesting a rich system of affixation or compounding.
7. Summary & Recommendations
Production Recommendations
| Component | Recommended | Rationale |
|---|---|---|
| Tokenizer | 64k BPE | Best compression (4.42x) |
| N-gram | 2-gram | Lowest perplexity (184) |
| Markov | Context-4 | Highest predictability (95.0%) |
| Embeddings | 100d | Balanced semantic capture and isotropy |
Appendix: Metrics Glossary & Interpretation Guide
This section provides definitions, intuitions, and guidance for interpreting the metrics used throughout this report.
Tokenizer Metrics
Compression Ratio
Definition: The ratio of characters to tokens (chars/token). Measures how efficiently the tokenizer represents text.
Intuition: Higher compression means fewer tokens needed to represent the same text, reducing sequence lengths for downstream models. A 3x compression means ~3 characters per token on average.
What to seek: Higher is generally better for efficiency, but extremely high compression may indicate overly aggressive merging that loses morphological information.
Average Token Length (Fertility)
Definition: Mean number of characters per token produced by the tokenizer.
Intuition: Reflects the granularity of tokenization. Longer tokens capture more context but may struggle with rare words; shorter tokens are more flexible but increase sequence length.
What to seek: Balance between 2-5 characters for most languages. Arabic/morphologically-rich languages may benefit from slightly longer tokens.
Unknown Token Rate (OOV Rate)
Definition: Percentage of tokens that map to the unknown/UNK token, indicating words the tokenizer cannot represent.
Intuition: Lower OOV means better vocabulary coverage. High OOV indicates the tokenizer encounters many unseen character sequences.
What to seek: Below 1% is excellent; below 5% is acceptable. BPE tokenizers typically achieve very low OOV due to subword fallback.
N-gram Model Metrics
Perplexity
Definition: Measures how "surprised" the model is by test data. Mathematically: 2^(cross-entropy). Lower values indicate better prediction.
Intuition: If perplexity is 100, the model is as uncertain as if choosing uniformly among 100 options at each step. A perplexity of 10 means effectively choosing among 10 equally likely options.
What to seek: Lower is better. Perplexity decreases with larger n-grams (more context). Values vary widely by language and corpus size.
Entropy
Definition: Average information content (in bits) needed to encode the next token given the context. Related to perplexity: perplexity = 2^entropy.
Intuition: High entropy means high uncertainty/randomness; low entropy means predictable patterns. Natural language typically has entropy between 1-4 bits per character.
What to seek: Lower entropy indicates more predictable text patterns. Entropy should decrease as n-gram size increases.
Coverage (Top-K)
Definition: Percentage of corpus occurrences explained by the top K most frequent n-grams.
Intuition: High coverage with few patterns indicates repetitive/formulaic text; low coverage suggests diverse vocabulary usage.
What to seek: Depends on use case. For language modeling, moderate coverage (40-60% with top-1000) is typical for natural text.
Markov Chain Metrics
Average Entropy
Definition: Mean entropy across all contexts, measuring average uncertainty in next-word prediction.
Intuition: Lower entropy means the model is more confident about what comes next. Context-1 has high entropy (many possible next words); Context-4 has low entropy (few likely continuations).
What to seek: Decreasing entropy with larger context sizes. Very low entropy (<0.1) indicates highly deterministic transitions.
Branching Factor
Definition: Average number of unique next tokens observed for each context.
Intuition: High branching = many possible continuations (flexible but uncertain); low branching = few options (predictable but potentially repetitive).
What to seek: Branching factor should decrease with context size. Values near 1.0 indicate nearly deterministic chains.
Predictability
Definition: Derived metric: (1 - normalized_entropy) × 100%. Indicates how deterministic the model's predictions are.
Intuition: 100% predictability means the next word is always certain; 0% means completely random. Real text falls between these extremes.
What to seek: Higher predictability for text generation quality, but too high (>98%) may produce repetitive output.
Vocabulary & Zipf's Law Metrics
Zipf's Coefficient
Definition: The slope of the log-log plot of word frequency vs. rank. Zipf's law predicts this should be approximately -1.
Intuition: A coefficient near -1 indicates the corpus follows natural language patterns where a few words are very common and most words are rare.
What to seek: Values between -0.8 and -1.2 indicate healthy natural language distribution. Deviations may suggest domain-specific or artificial text.
R² (Coefficient of Determination)
Definition: Measures how well the linear fit explains the frequency-rank relationship. Ranges from 0 to 1.
Intuition: R² near 1.0 means the data closely follows Zipf's law; lower values indicate deviation from expected word frequency patterns.
What to seek: R² > 0.95 is excellent; > 0.99 indicates near-perfect Zipf adherence typical of large natural corpora.
Vocabulary Coverage
Definition: Cumulative percentage of corpus tokens accounted for by the top N words.
Intuition: Shows how concentrated word usage is. If top-100 words cover 50% of text, the corpus relies heavily on common words.
What to seek: Top-100 covering 30-50% is typical. Higher coverage indicates more repetitive text; lower suggests richer vocabulary.
Word Embedding Metrics
Isotropy
Definition: Measures how uniformly distributed vectors are in the embedding space. Computed as the ratio of minimum to maximum singular values.
Intuition: High isotropy (near 1.0) means vectors spread evenly in all directions; low isotropy means vectors cluster in certain directions, reducing expressiveness.
What to seek: Higher isotropy generally indicates better-quality embeddings. Values > 0.1 are reasonable; > 0.3 is good. Lower-dimensional embeddings tend to have higher isotropy.
Average Norm
Definition: Mean magnitude (L2 norm) of word vectors in the embedding space.
Intuition: Indicates the typical "length" of vectors. Consistent norms suggest stable training; high variance may indicate some words are undertrained.
What to seek: Relatively consistent norms across models. The absolute value matters less than consistency (low std deviation).
Cosine Similarity
Definition: Measures angular similarity between vectors, ranging from -1 (opposite) to 1 (identical direction).
Intuition: Words with similar meanings should have high cosine similarity. This is the standard metric for semantic relatedness in embeddings.
What to seek: Semantically related words should score > 0.5; unrelated words should be near 0. Synonyms often score > 0.7.
t-SNE Visualization
Definition: t-Distributed Stochastic Neighbor Embedding - a dimensionality reduction technique that preserves local structure for visualization.
Intuition: Clusters in t-SNE plots indicate groups of semantically related words. Spread indicates vocabulary diversity; tight clusters suggest semantic coherence.
What to seek: Meaningful clusters (e.g., numbers together, verbs together). Avoid over-interpreting distances - t-SNE preserves local, not global, structure.
General Interpretation Guidelines
- Compare within model families: Metrics are most meaningful when comparing models of the same type (e.g., 8k vs 64k tokenizer).
- Consider trade-offs: Better performance on one metric often comes at the cost of another (e.g., compression vs. OOV rate).
- Context matters: Optimal values depend on downstream tasks. Text generation may prioritize different metrics than classification.
- Corpus influence: All metrics are influenced by corpus characteristics. Wikipedia text differs from social media or literature.
- Language-specific patterns: Morphologically rich languages (like Arabic) may show different optimal ranges than analytic languages.
Visualizations Index
| Visualization | Description |
|---|---|
| Tokenizer Compression | Compression ratios by vocabulary size |
| Tokenizer Fertility | Average token length by vocabulary |
| Tokenizer OOV | Unknown token rates |
| Tokenizer Total Tokens | Total tokens by vocabulary |
| N-gram Perplexity | Perplexity by n-gram size |
| N-gram Entropy | Entropy by n-gram size |
| N-gram Coverage | Top pattern coverage |
| N-gram Unique | Unique n-gram counts |
| Markov Entropy | Entropy by context size |
| Markov Branching | Branching factor by context |
| Markov Contexts | Unique context counts |
| Zipf's Law | Frequency-rank distribution with fit |
| Vocab Frequency | Word frequency distribution |
| Top 20 Words | Most frequent words |
| Vocab Coverage | Cumulative coverage curve |
| Embedding Isotropy | Vector space uniformity |
| Embedding Norms | Vector magnitude distribution |
| Embedding Similarity | Word similarity heatmap |
| Nearest Neighbors | Similar words for key terms |
| t-SNE Words | 2D word embedding visualization |
| t-SNE Sentences | 2D sentence embedding visualization |
| Position Encoding | Encoding method comparison |
| Model Sizes | Storage requirements |
| Performance Dashboard | Comprehensive performance overview |
About This Project
Data Source
Models trained on wikipedia-monthly - a monthly snapshot of Wikipedia articles across 300+ languages.
Project
A project by Wikilangs - Open-source NLP models for every Wikipedia language.
Maintainer
Citation
If you use these models in your research, please cite:
@misc{wikilangs2025,
author = {Kamali, Omar},
title = {Wikilangs: Open NLP Models for Wikipedia Languages},
year = {2025},
doi = {10.5281/zenodo.18073153},
publisher = {Zenodo},
url = {https://huggingface.co/wikilangs}
institution = {Omneity Labs}
}
License
MIT License - Free for academic and commercial use.
Links
- 🌐 Website: wikilangs.org
- 🤗 Models: huggingface.co/wikilangs
- 📊 Data: wikipedia-monthly
- 👤 Author: Omar Kamali
- 🤝 Sponsor: Featherless AI
Generated by Wikilangs Models Pipeline
Report Date: 2026-01-10 22:42:51



















