Lithuanian - Wikilangs Models
Comprehensive Research Report & Full Ablation Study
This repository contains NLP models trained and evaluated by Wikilangs, specifically on Lithuanian 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 | 3.661x | 3.66 | 0.1102% | 2,105,079 |
| 16k | 4.090x | 4.09 | 0.1231% | 1,884,341 |
| 32k | 4.453x | 4.45 | 0.1340% | 1,730,520 |
| 64k | 4.757x π | 4.76 | 0.1431% | 1,620,062 |
Tokenization Examples
Below are sample sentences tokenized with each vocabulary size:
Sample 1: Vilkonys β kaimas PanevΔΕΎio rajono savivaldybΔje, 2 km nuo Raguvos. Gyventojai Ε ...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βvilk on ys ββ βkaimas βpanevΔΕΎio βrajono βsavivaldybΔje , β ... (+11 more) |
21 |
| 16k | βvilk onys ββ βkaimas βpanevΔΕΎio βrajono βsavivaldybΔje , β 2 ... (+10 more) |
20 |
| 32k | βvilk onys ββ βkaimas βpanevΔΕΎio βrajono βsavivaldybΔje , β 2 ... (+9 more) |
19 |
| 64k | βvilk onys ββ βkaimas βpanevΔΕΎio βrajono βsavivaldybΔje , β 2 ... (+9 more) |
19 |
Sample 2: DΕΎufros savivaldybΔ () β Libijos savivaldybΔ Ε‘alies centrinΔje dalyje, Sacharos ...
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βdΕΎ u f ros βsavivaldybΔ β() ββ βlib ijos βsavivaldybΔ ... (+18 more) |
28 |
| 16k | βdΕΎ uf ros βsavivaldybΔ β() ββ βlib ijos βsavivaldybΔ βΕ‘alies ... (+15 more) |
25 |
| 32k | βdΕΎ uf ros βsavivaldybΔ β() ββ βlibijos βsavivaldybΔ βΕ‘alies βcentrinΔje ... (+12 more) |
22 |
| 64k | βdΕΎ uf ros βsavivaldybΔ β() ββ βlibijos βsavivaldybΔ βΕ‘alies βcentrinΔje ... (+12 more) |
22 |
Sample 3: DΕ«doriΕ‘kiai β viensΔdis BirΕΎΕ³ rajono savivaldybΔje, 6 km Δ― vakarus nuo PabirΕΎΔs....
| Vocab | Tokens | Count |
|---|---|---|
| 8k | βdΕ« do riΕ‘k iai ββ βviensΔdis βbirΕΎΕ³ βrajono βsavivaldybΔje , ... (+15 more) |
25 |
| 16k | βdΕ« do riΕ‘k iai ββ βviensΔdis βbirΕΎΕ³ βrajono βsavivaldybΔje , ... (+15 more) |
25 |
| 32k | βdΕ« do riΕ‘k iai ββ βviensΔdis βbirΕΎΕ³ βrajono βsavivaldybΔje , ... (+15 more) |
25 |
| 64k | βdΕ« do riΕ‘kiai ββ βviensΔdis βbirΕΎΕ³ βrajono βsavivaldybΔje , β ... (+12 more) |
22 |
Key Findings
- Best Compression: 64k achieves 4.757x compression
- Lowest UNK Rate: 8k with 0.1102% 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 | 196,143 | 17.58 | 951,489 | 6.6% | 16.9% |
| 2-gram | Subword | 347 π | 8.44 | 16,291 | 61.2% | 98.5% |
| 3-gram | Word | 370,705 | 18.50 | 1,291,283 | 4.1% | 12.0% |
| 3-gram | Subword | 3,304 | 11.69 | 131,904 | 20.0% | 64.1% |
| 4-gram | Word | 774,264 | 19.56 | 2,157,224 | 3.3% | 9.4% |
| 4-gram | Subword | 21,025 | 14.36 | 755,683 | 8.5% | 31.1% |
| 5-gram | Word | 702,338 | 19.42 | 1,649,947 | 3.1% | 8.5% |
| 5-gram | Subword | 92,546 | 16.50 | 2,569,308 | 4.6% | 17.5% |
Top 5 N-grams by Size
2-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | nuo m |
80,598 |
| 2 | taip pat |
61,102 |
| 3 | m m |
49,221 |
| 4 | km Δ― |
40,737 |
| 5 | g m |
39,476 |
3-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | rajono savivaldybΔs gyvenvietΔs |
21,760 |
| 2 | Ε‘altiniai rajono savivaldybΔs |
18,042 |
| 3 | gyventojai Ε‘altiniai rajono |
15,946 |
| 4 | pr m e |
15,933 |
| 5 | 0 0 0 |
11,090 |
4-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | Ε‘altiniai rajono savivaldybΔs gyvenvietΔs |
17,791 |
| 2 | gyventojai Ε‘altiniai rajono savivaldybΔs |
15,570 |
| 3 | m pr m e |
9,199 |
| 4 | 0 0 0 0 |
6,658 |
| 5 | Δ― Ε‘iaurΔs rytus nuo |
6,349 |
5-grams (Word):
| Rank | N-gram | Count |
|---|---|---|
| 1 | gyventojai Ε‘altiniai rajono savivaldybΔs gyvenvietΔs |
15,554 |
| 2 | km Δ― Ε‘iaurΔs rytus nuo |
5,574 |
| 3 | km Δ― Ε‘iaurΔs vakarus nuo |
4,918 |
| 4 | 0 0 0 0 0 |
4,143 |
| 5 | general information about the player |
2,888 |
2-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | s _ |
8,108,761 |
| 2 | o _ |
4,732,529 |
| 3 | i n |
4,492,534 |
| 4 | . _ |
4,477,090 |
| 5 | a s |
3,925,055 |
3-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | o s _ |
2,303,630 |
| 2 | a s _ |
2,033,580 |
| 3 | _ p a |
1,580,889 |
| 4 | i n i |
1,432,110 |
| 5 | a i _ |
1,247,013 |
4-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | _ m . _ |
1,006,887 |
| 2 | _ i r _ |
1,000,574 |
| 3 | i j o s |
645,380 |
| 4 | j o s _ |
630,230 |
| 5 | t a s _ |
487,967 |
5-grams (Subword):
| Rank | N-gram | Count |
|---|---|---|
| 1 | i j o s _ |
560,980 |
| 2 | . _ m . _ |
345,387 |
| 3 | b u v o _ |
340,153 |
| 4 | _ b u v o |
328,906 |
| 5 | l i e t u |
311,837 |
Key Findings
- Best Perplexity: 2-gram (subword) with 347
- Entropy Trend: Decreases with larger n-grams (more predictable)
- Coverage: Top-1000 patterns cover ~17% 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 | 1.0333 | 2.047 | 10.88 | 1,497,676 | 0.0% |
| 1 | Subword | 1.0306 | 2.043 | 6.87 | 9,691 | 0.0% |
| 2 | Word | 0.2905 | 1.223 | 1.79 | 16,264,065 | 71.0% |
| 2 | Subword | 0.6783 | 1.600 | 4.61 | 66,441 | 32.2% |
| 3 | Word | 0.0931 | 1.067 | 1.18 | 29,101,762 | 90.7% |
| 3 | Subword | 0.7377 | 1.667 | 4.28 | 306,205 | 26.2% |
| 4 | Word | 0.0375 π | 1.026 | 1.06 | 34,194,540 | 96.3% |
| 4 | Subword | 0.7065 | 1.632 | 3.54 | 1,310,778 | 29.3% |
Generated Text Samples (Word-based)
Below are text samples generated from each word-based Markov chain model:
Context Size 1:
m m new york reprint der lehre von trips as ratas paskutinis vicekaralius vΔliau tiΕ‘keviΔiaus logois...ir ΕΎagarΔs vidurinΔs mokyklos patalpose auΕ‘ros pradΕΎios rokas beliukeviΔius g m rugpjΕ«tΔ― jo sΕ«nΕ³ dΕΎe...buvo prilyginti taip pat deltuvos ΕΎemΔ Ε‘iose pareigose g m atvyko Δ― pasaulio lietuviΕ³ tarybos nariΕ³
Context Size 2:
nuo m kursuoja trollino 15 ac Ε‘altiniai miestai miestai apygardos apygardos vakarinius krantus skala...taip pat katalikiΕ‘kos pakraipos Ε‘v sebastijono atvaizdas andrΔja mantenja mirΔ m balandΕΎio 18 m bala...m m gruodΕΎio 11 d vilnius smuikininkas pedagogas vargonininkas chorvedys muzikos mokytojas lankydama...
Context Size 3:
Ε‘altiniai rajono savivaldybΔs gyvenvietΔs miesto dalysgyventojai Ε‘altiniai rajono savivaldybΔs geleΕΎinkelio stotys kultΕ«ros vertybΔs geleΕΎinkelio stotys s...pr m e galΔjo bΕ«ti knoso uostas Δ―kΕ«rimas dabartinΔ― heraklionΔ 824 m Δ―kΕ«rΔ saracΔnai iΕ‘varyti iΕ‘ anda...
Context Size 4:
gyventojai Ε‘altiniai rajono savivaldybΔs gyvenvietΔs kaimai aukΕ‘taitijos nacionaliniame parke kaimaim pr m e jΕ³ indΔlis Δ― matematikΔ astronomijΔ ir medicinΔ bΕ«damas 16 metΕ³ pagarsΔjo iΕ‘gydΔs bucharos ...0 0 0 0 0 0 0 1 0 4 1 1 0 ii grupΔ komandatΕ‘k rungt laim lyg
Generated Text Samples (Subword-based)
Below are text samples generated from each subword-based Markov chain model:
Context Size 1:
_viΔingauve_us_Δ―i_g_vilie_jΔ _alyadiuvosΕakaikari
Context Size 2:
s_kopiniai_vaΕΎodao_bel_patvΔ_citasingotentrauliteli
Context Size 3:
os_karius_sodΕ³_bΕ«tas_ii_panΕ³_siniais_pastame_garalianΔ
Context Size 4:
_m._laipΔdoje_yra_k_ir_dvejΕ³_ΕΎvaigΕΎdΔ_ijos_karoliuojas,_a
Key Findings
- Best Predictability: Context-4 (word) with 96.3% predictability
- Branching Factor: Decreases with context size (more deterministic)
- Memory Trade-off: Larger contexts require more storage (1,310,778 contexts)
- Recommendation: Context-3 or Context-4 for text generation
4. Vocabulary Analysis
Statistics
| Metric | Value |
|---|---|
| Vocabulary Size | 719,992 |
| Total Tokens | 41,466,357 |
| Mean Frequency | 57.59 |
| Median Frequency | 4 |
| Frequency Std Dev | 2237.16 |
Most Common Words
| Rank | Word | Frequency |
|---|---|---|
| 1 | m | 1,249,293 |
| 2 | ir | 1,005,030 |
| 3 | buvo | 329,252 |
| 4 | Δ― | 322,738 |
| 5 | nuo | 252,061 |
| 6 | d | 244,466 |
| 7 | iΕ‘ | 222,420 |
| 8 | su | 217,987 |
| 9 | 1 | 212,417 |
| 10 | yra | 198,413 |
Least Common Words (from vocabulary)
| Rank | Word | Frequency |
|---|---|---|
| 1 | triumphal | 2 |
| 2 | sawano | 2 |
| 3 | taisen | 2 |
| 4 | iryu | 2 |
| 5 | nzk | 2 |
| 6 | lorensavo | 2 |
| 7 | gauchos | 2 |
| 8 | architekturze | 2 |
| 9 | sztuce | 2 |
| 10 | ΕubieΕski | 2 |
Zipf's Law Analysis
| Metric | Value |
|---|---|
| Zipf Coefficient | 0.9393 |
| RΒ² (Goodness of Fit) | 0.994466 |
| Adherence Quality | excellent |
Coverage Analysis
| Top N Words | Coverage |
|---|---|
| Top 100 | 23.0% |
| Top 1,000 | 44.0% |
| Top 5,000 | 62.7% |
| Top 10,000 | 70.6% |
Key Findings
- Zipf Compliance: RΒ²=0.9945 indicates excellent adherence to Zipf's law
- High Frequency Dominance: Top 100 words cover 23.0% of corpus
- Long Tail: 709,992 words needed for remaining 29.4% 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 | 0.8202 π | 0.3473 | N/A | N/A |
| mono_64d | 64 | 0.8013 | 0.2803 | N/A | N/A |
| mono_128d | 128 | 0.7515 | 0.2219 | N/A | N/A |
| aligned_32d | 32 | 0.8202 | 0.3470 | 0.1200 | 0.4580 |
| aligned_64d | 64 | 0.8013 | 0.2841 | 0.3160 | 0.7180 |
| aligned_128d | 128 | 0.7515 | 0.2188 | 0.4260 | 0.7780 |
Key Findings
- Best Isotropy: mono_32d with 0.8202 (more uniform distribution)
- Semantic Density: Average pairwise similarity of 0.2832. Lower values indicate better semantic separation.
- Alignment Quality: Aligned models achieve up to 42.6% 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 | -0.511 | Low formulaic content | - |
6.2 Affix Inventory (Productive Units)
These are the most productive prefixes and suffixes identified by sampling the vocabulary for global substitutability patterns. A unit is considered an affix if stripping it leaves a valid stem that appears in other contexts.
Productive Prefixes
| Prefix | Examples |
|---|---|
-s |
stambinant, smutki, sanio |
-a |
abaujaus, atidΔliojimΔ , antigono |
-ma |
maΕ‘kΔ, marΕ‘ruto, maceika |
-k |
kiΕ‘enes, kaljan, khan |
-m |
maΕ‘kΔ, mΓ‘gica, mergystΔs |
-ka |
kaljan, kastilija, kalanti |
-p |
praktikuoti, partenopΔ, pajΔ |
-pa |
partenopΔ, pajΔ, paitensis |
Productive Suffixes
| Suffix | Examples |
|---|---|
-s |
kiΕ‘enes, goblets, hallas |
-as |
hallas, anamas, kuartas |
-i |
praktikuoti, smutki, trΕ«ki |
-is |
alramis, paitensis, refrakcinis |
-o |
antigono, sanio, sliesoraiΔio |
-e |
uΕΎantyje, geheimnisse, Ε‘turmane |
-a |
mΓ‘gica, arhitektΕ«ra, susuka |
-ai |
antikomunistiniai, uΕΎkuriai, laurinaviΔiai |
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 |
|---|---|---|---|
iniΕ³ |
1.80x | 283 contexts | ainiΕ³, ΕΎiniΕ³, niniΕ³ |
etuv |
2.37x | 59 contexts | betuvΔ, rietuvΔ, sietuvΔ |
yven |
1.82x | 148 contexts | lyven, gyvenu, gyvenΔ |
inim |
1.53x | 306 contexts | minim, dinim, minime |
gyve |
1.86x | 92 contexts | gyvenu, gyvenΔ , gyvenc |
iaur |
1.66x | 139 contexts | iauri, ΕΎiaurΕ³, siaure |
tinΔ |
1.34x | 421 contexts | etinΔ, matinΔ, vatinΔ |
ltin |
1.42x | 229 contexts | altin, altino, baltin |
ausi |
1.47x | 173 contexts | kausi, gausi, ausim |
tuvo |
1.98x | 45 contexts | tuvos, tuvoje, bytuvo |
ajon |
1.66x | 80 contexts | fajon, rajon, pajon |
ietu |
1.54x | 104 contexts | vietu, kietu, lietu |
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 |
|---|---|---|---|
-p |
-s |
299 words | pingus, plΔtotos |
-s |
-s |
261 words | slaugymas, statybiniais |
-k |
-s |
206 words | kreatininas, komarnicos |
-a |
-s |
202 words | ajagozas, apsukrus |
-b |
-s |
142 words | bubles, begΔdis |
-d |
-s |
128 words | dramblys, dΕΎinhanas |
-p |
-i |
124 words | piktindamiesi, pirkiniui |
-m |
-s |
114 words | monofizitais, meniΕ‘kais |
-s |
-i |
97 words | stasiΕ«nieΔiai, segmentuojasi |
-s |
-o |
85 words | slomo, skaitytojo |
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 |
|---|---|---|---|
| stankiΕ‘kiuose | stankiΕ‘kiuo-s-e |
7.5 | s |
| pertekusi | perteku-s-i |
7.5 | s |
| ekranuose | ekranuo-s-e |
7.5 | s |
| baΔkonyse | baΔkony-s-e |
7.5 | s |
| ramonuose | ramonuo-s-e |
7.5 | s |
| komentaruose | komentaruo-s-e |
7.5 | s |
| hidnotrija | hidnotr-i-ja |
7.5 | i |
| Ε‘audyklose | Ε‘audyklo-s-e |
7.5 | s |
| nuomojosi | nuomojo-s-i |
7.5 | s |
| suvynioja | suvyni-o-ja |
7.5 | o |
| riboΕΎenkliai | riboΕΎenkl-i-ai |
7.5 | i |
| potvarkiuose | potvarkiuo-s-e |
7.5 | s |
| antigvosΔ | antigvo-s-Δ
|
7.5 | s |
| uΕΎutekiuose | uΕΎutekiuo-s-e |
7.5 | s |
| muitinΔse | muitinΔ-s-e |
7.5 | s |
6.6 Linguistic Interpretation
Automated Insight: The language Lithuanian 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 (4.76x) |
| N-gram | 2-gram | Lowest perplexity (347) |
| Markov | Context-4 | Highest predictability (96.3%) |
| 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: 2026-01-14 22:52:53



















