--- language: am language_name: AM language_family: semitic_ethiopic tags: - wikilangs - nlp - tokenizer - embeddings - n-gram - markov - wikipedia - monolingual - family-semitic_ethiopic license: mit library_name: wikilangs pipeline_tag: feature-extraction 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: 3.278 - name: best_isotropy type: isotropy value: 0.9070 - name: vocabulary_size type: vocab value: 108024 generated: 2025-12-27 --- # AM - Wikilangs Models ## Comprehensive Research Report & Full Ablation Study This repository contains NLP models trained and evaluated by Wikilangs, specifically on **AM** Wikipedia data. We analyze tokenizers, n-gram models, Markov chains, vocabulary statistics, and word embeddings. ## ๐Ÿ“‹ Repository Contents ### Models & Assets - Tokenizers (8k, 16k, 32k, 64k) - N-gram models (2, 3, 4-gram) - Markov chains (context of 1, 2, 3 and 4) - Subword N-gram and Markov chains - Embeddings in various sizes and dimensions - Language Vocabulary - Language Statistics ![Performance Dashboard](visualizations/performance_dashboard.png) ### Analysis and Evaluation - [1. Tokenizer Evaluation](#1-tokenizer-evaluation) - [2. N-gram Model Evaluation](#2-n-gram-model-evaluation) - [3. Markov Chain Evaluation](#3-markov-chain-evaluation) - [4. Vocabulary Analysis](#4-vocabulary-analysis) - [5. Word Embeddings Evaluation](#5-word-embeddings-evaluation) - [6. Summary & Recommendations](#6-summary--recommendations) - [Metrics Glossary](#appendix-metrics-glossary--interpretation-guide) - [Visualizations Index](#visualizations-index) --- ## 1. Tokenizer Evaluation ![Tokenizer Compression](visualizations/tokenizer_compression.png) ### Results | Vocab Size | Compression | Avg Token Len | UNK Rate | Total Tokens | |------------|-------------|---------------|----------|--------------| | **8k** | 2.456x | 2.43 | 0.1639% | 455,103 | | **16k** | 2.758x | 2.73 | 0.1841% | 405,251 | | **32k** | 3.035x | 3.00 | 0.2026% | 368,183 | | **64k** | 3.278x ๐Ÿ† | 3.24 | 0.2188% | 340,895 | ### Tokenization Examples Below are sample sentences tokenized with each vocabulary size: **Sample 1:** `' แ‹จ แ‰ปแ‹ญแŠ“ แŠ•แŒ‰แˆฅ แАแ‰ แˆญแข แ‹‹แ‰ข แˆ˜แŒฝแˆแแ‰ต แˆ˜แ‹ฐแ‰ฅ:แ‹จแ‰ปแ‹ญแŠ“ แАแŒˆแˆฅแ‰ณแ‰ต` | Vocab | Tokens | Count | |-------|--------|-------| | 8k | `โ–' โ–แ‹จ โ–แ‰ปแ‹ญแŠ“ โ–แŠ•แŒ‰แˆฅ โ–แАแ‰ แˆญแข โ–แ‹‹แ‰ข โ–แˆ˜แŒฝแˆแแ‰ต โ–แˆ˜แ‹ฐแ‰ฅ : แ‹จแ‰ปแ‹ญแŠ“ ... (+1 more)` | 11 | | 16k | `โ–' โ–แ‹จ โ–แ‰ปแ‹ญแŠ“ โ–แŠ•แŒ‰แˆฅ โ–แАแ‰ แˆญแข โ–แ‹‹แ‰ข โ–แˆ˜แŒฝแˆแแ‰ต โ–แˆ˜แ‹ฐแ‰ฅ : แ‹จแ‰ปแ‹ญแŠ“ ... (+1 more)` | 11 | | 32k | `โ–' โ–แ‹จ โ–แ‰ปแ‹ญแŠ“ โ–แŠ•แŒ‰แˆฅ โ–แАแ‰ แˆญแข โ–แ‹‹แ‰ข โ–แˆ˜แŒฝแˆแแ‰ต โ–แˆ˜แ‹ฐแ‰ฅ : แ‹จแ‰ปแ‹ญแŠ“ ... (+1 more)` | 11 | | 64k | `โ–' โ–แ‹จ โ–แ‰ปแ‹ญแŠ“ โ–แŠ•แŒ‰แˆฅ โ–แАแ‰ แˆญแข โ–แ‹‹แ‰ข โ–แˆ˜แŒฝแˆแแ‰ต โ–แˆ˜แ‹ฐแ‰ฅ : แ‹จแ‰ปแ‹ญแŠ“ ... (+1 more)` | 11 | **Sample 2:** `แŠขแ‰ตแ‹ฎแŒตแ‹ซ แ‹แˆตแŒฅ แ‹จแˆšแˆฐแˆซ แ‹จแˆแŒแ‰ฅ แŠ แ‹ญแАแ‰ต แˆฒแˆ†แŠ•แฃ แ‹จแˆšแˆฐแˆซแ‹แˆ แŠจแˆฑแแˆตแŠ•แ‹ดแŠ“ แŠ แŠ•แ‹ต แŠ แŠ•แ‹ต แŒŠแ‹œแˆ แˆฝแˆแ‰ฅแˆซ แ‰†แˆŽ แАแ‹แข แŠ แ‹˜แŒˆแŒƒแŒ€แ‰ต แˆŠแ‰ฐ...` | Vocab | Tokens | Count | |-------|--------|-------| | 8k | `โ–แŠขแ‰ตแ‹ฎแŒตแ‹ซ โ–แ‹แˆตแŒฅ โ–แ‹จแˆšแˆฐแˆซ โ–แ‹จแˆแŒแ‰ฅ โ–แŠ แ‹ญแАแ‰ต โ–แˆฒแˆ†แŠ•แฃ โ–แ‹จแˆšแˆฐแˆซ แ‹แˆ โ–แŠจแˆฑ แ ... (+20 more)` | 30 | | 16k | `โ–แŠขแ‰ตแ‹ฎแŒตแ‹ซ โ–แ‹แˆตแŒฅ โ–แ‹จแˆšแˆฐแˆซ โ–แ‹จแˆแŒแ‰ฅ โ–แŠ แ‹ญแАแ‰ต โ–แˆฒแˆ†แŠ•แฃ โ–แ‹จแˆšแˆฐแˆซแ‹แˆ โ–แŠจแˆฑ แ แˆตแŠ• ... (+16 more)` | 26 | | 32k | `โ–แŠขแ‰ตแ‹ฎแŒตแ‹ซ โ–แ‹แˆตแŒฅ โ–แ‹จแˆšแˆฐแˆซ โ–แ‹จแˆแŒแ‰ฅ โ–แŠ แ‹ญแАแ‰ต โ–แˆฒแˆ†แŠ•แฃ โ–แ‹จแˆšแˆฐแˆซแ‹แˆ โ–แŠจแˆฑ แ แˆตแŠ•แ‹ด ... (+14 more)` | 24 | | 64k | `โ–แŠขแ‰ตแ‹ฎแŒตแ‹ซ โ–แ‹แˆตแŒฅ โ–แ‹จแˆšแˆฐแˆซ โ–แ‹จแˆแŒแ‰ฅ โ–แŠ แ‹ญแАแ‰ต โ–แˆฒแˆ†แŠ•แฃ โ–แ‹จแˆšแˆฐแˆซแ‹แˆ โ–แŠจแˆฑ แ แˆตแŠ•แ‹ด ... (+14 more)` | 24 | **Sample 3:** `1 January 1955 - 11 September 1955 แŠฅ.แŠค.แŠฃ. = 1947 แŠ .แˆ. 12 September 1955 - 31 Dec...` | Vocab | Tokens | Count | |-------|--------|-------| | 8k | `โ– 1 โ–january โ– 1 9 5 5 โ–- โ– ... (+59 more)` | 69 | | 16k | `โ– 1 โ–january โ– 1 9 5 5 โ–- โ– ... (+59 more)` | 69 | | 32k | `โ– 1 โ–january โ– 1 9 5 5 โ–- โ– ... (+59 more)` | 69 | | 64k | `โ– 1 โ–january โ– 1 9 5 5 โ–- โ– ... (+59 more)` | 69 | ### Key Findings - **Best Compression:** 64k achieves 3.278x compression - **Lowest UNK Rate:** 8k with 0.1639% 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 ![N-gram Perplexity](visualizations/ngram_perplexity.png) ![N-gram Coverage](visualizations/ngram_coverage.png) ### Results | N-gram | Perplexity | Entropy | Unique N-grams | Top-100 Coverage | Top-1000 Coverage | |--------|------------|---------|----------------|------------------|-------------------| | **2-gram** | 10,759 ๐Ÿ† | 13.39 | 48,164 | 21.6% | 40.3% | | **2-gram** | 2,321 ๐Ÿ† | 11.18 | 26,048 | 32.4% | 67.6% | | **3-gram** | 16,194 | 13.98 | 68,935 | 19.7% | 36.8% | | **3-gram** | 21,529 | 14.39 | 173,382 | 11.5% | 34.1% | | **4-gram** | 45,509 | 15.47 | 148,975 | 14.6% | 27.1% | | **4-gram** | 104,202 | 16.67 | 623,179 | 6.7% | 19.0% | ### Top 5 N-grams by Size **2-grams:** | Rank | N-gram | Count | |------|--------|-------| | 1 | `แАแ‹ แข` | 21,098 | | 2 | `แˆ˜แ‹ฐแ‰ฅ :` | 19,279 | | 3 | `แก แก` | 9,600 | | 4 | `แАแ‰ แˆญ แข` | 6,290 | | 5 | `แ‹“ .` | 6,166 | **3-grams:** | Rank | N-gram | Count | |------|--------|-------| | 1 | `แˆแˆณแˆŒ แАแ‹ แข` | 5,880 | | 2 | `แ‹จแŠ แˆ›แˆญแŠ› แˆแˆณแˆŒ แАแ‹` | 5,832 | | 3 | `แ‹“ . แˆ` | 5,831 | | 4 | `แข แˆ˜แ‹ฐแ‰ฅ :` | 5,106 | | 5 | `. แˆ .` | 4,919 | **4-grams:** | Rank | N-gram | Count | |------|--------|-------| | 1 | `แ‹จแŠ แˆ›แˆญแŠ› แˆแˆณแˆŒ แАแ‹ แข` | 5,832 | | 2 | `แ‹“ . แˆ .` | 4,753 | | 3 | `แŠฅ . แŠค .` | 4,046 | | 4 | `. แŠค . แŠ ` | 3,983 | | 5 | `แˆแˆณแˆŒ แАแ‹ แข แ‰ตแˆญแŒ‰แˆ™` | 3,720 | ### Key Findings - **Best Perplexity:** 2-gram with 2,321 - **Entropy Trend:** Decreases with larger n-grams (more predictable) - **Coverage:** Top-1000 patterns cover ~19% of corpus - **Recommendation:** 4-gram or 5-gram for best predictive performance --- ## 3. Markov Chain Evaluation ![Markov Entropy](visualizations/markov_entropy.png) ![Markov Branching](visualizations/markov_branching.png) ### Results | Context | Avg Entropy | Perplexity | Branching Factor | Unique Contexts | Predictability | |---------|-------------|------------|------------------|-----------------|----------------| | **1** | 0.6978 | 1.622 | 4.88 | 254,884 | 30.2% | | **1** | 1.4402 | 2.714 | 22.49 | 2,349 | 0.0% | | **2** | 0.1891 | 1.140 | 1.44 | 1,243,645 | 81.1% | | **2** | 1.1315 | 2.191 | 7.49 | 52,808 | 0.0% | | **3** | 0.0627 | 1.044 | 1.12 | 1,794,848 | 93.7% | | **3** | 0.6676 | 1.588 | 3.40 | 395,365 | 33.2% | | **4** | 0.0256 ๐Ÿ† | 1.018 | 1.04 | 2,006,381 | 97.4% | | **4** | 0.4515 ๐Ÿ† | 1.367 | 2.11 | 1,342,049 | 54.9% | ### Generated Text Samples Below are text samples generated from each Markov chain model: **Context Size 1:** 1. `แข แ‰ตแˆแˆ…แˆญแ‰ต แ‰คแ‰ต แАแŒฃแŒฅแˆŽ แˆ˜แŒˆแŠ•แ‹˜แ‰ฅ แ‹ญแŠ–แˆญแ‰ แ‰ณแˆ แ‰ฐแ‰ฅแˆŽ แ‹จแˆšแ‰ณแˆ˜แАแ‹ แ‹จแ‰ถแˆชแŠ– แ‰€แŠ–แŠ“ แˆ›แˆตแ‰ฐแˆ›แˆญแŠ“ แ‰ตแˆแˆ…แˆญแ‰ต แˆฝแŒแŒแˆญ แˆ˜แŠ•แŒแˆตแ‰ต 1643 -` 2. `แก แˆ›แˆตแˆจแŒƒ แŠฅแŠ•แ‹ฐแˆŒแˆˆ แ‹ญแ‰†แŒ แˆซแˆ แ‹จแŠ แˆ›แˆญแŠ› แˆแˆณแˆŒ แАแ‹ แˆ˜แ‹ฐแ‰ฅ : / wiki / div id ) 2002` 3. `. ) แŠฅแŠ“ แ‹จแ‰ แˆˆแŒ  แŠฅแ‹แАแ‰ต แˆ†แŠ– แˆˆแ“แ‹แˆœแˆซแˆต แŠญแˆˆแ‰ฅ แ‰ แˆแˆจแˆญ แฃ 1943 ) แ‹จแŠ แˆนแˆญ แŠ•แŒ‰แˆฅ แ‰ณแˆ‹แ‰ แ’แ‰ฐแˆญ` **Context Size 2:** 1. `แАแ‹ แข แ‰ตแˆญแŒ‰แˆ™ แˆ˜แˆแˆต แˆฒแ‰ณแŒฃ แฃ แ‹แˆแ‰ณ แ‰ฐแˆแŒฅแˆฎแ‹ แ‹จแˆ†แА แŒแˆฉแˆ แ‹ตแˆแŒปแ‹Š แАแ‹ แข แ‰ 13แŠ›แ‹ แŠญแแˆˆ แ‹˜แˆ˜แŠ• แ‹จแ‹ชแŒ‚แŠ•แŒ` 2. `แˆ˜แ‹ฐแ‰ฅ : แ‹จแŠฎแˆชแ‹ซ แАแŒˆแˆฅแ‰ณแ‰ต` 3. `แก แก แ‰ แŠ แŠซแˆ‹แ‹Š แŒˆแŒฝแ‰ณ แŠฅแŠ“ แŠจแˆ…แ‹แ‰ก แŠ แŠ•แ‹ต แŠ แˆซแ‰ฐแŠ›แ‹แŠ• แ‹ญแˆธแแŠ“แˆ แข แˆแŠ•แˆ แŠฅแŠ•แŠณแŠ• แ‰ฐแˆ˜แˆณแˆณแ‹ญ แŒฅแˆแˆจแ‰ต แŠจแ‰ฅแ‹™ แŠ แˆฅแˆญแ‰ฐ แ‹“แˆ˜แ‰ณแ‰ต` **Context Size 3:** 1. `แˆแˆณแˆŒ แАแ‹ แข แ‹˜แˆ˜แА แŒแˆญแˆแ‰ขแŒฅ แ‹แˆป แ‹ˆแ‹ฐ แˆฐแˆญแ‹ถ แŠ แˆ…แ‹ซ แ‹ˆแ‹ฐ แˆŠแŒฅ แ‹˜แˆ˜แŠ• แŠฅแŠ•แ‹ฐแŠ•แŒ‰แˆฑ แŠ แ‹แ‹ตแˆ› แŠฅแŠ•แ‹ฐแŠ•แ‹แˆฑ แ‹จแŠ แˆ›แˆญแŠ› แˆแˆณแˆŒ แАแ‹` 2. `แ‹จแŠ แˆ›แˆญแŠ› แˆแˆณแˆŒ แАแ‹ แข แ‰ตแˆญแŒ‰แˆ™ แˆ˜แ‹ฐแ‰ฅ : แ‹ซแˆแ‰ฐแ‰ฐแˆจแŒŽแˆ˜ แˆแˆณแˆŒ แˆ˜แ‹ฐแ‰ฅ : แ‰ฐแˆจแ‰ตแŠ“ แˆแˆณแˆŒ แˆ˜แ‹ฐแ‰ฅ : แ‰ฐแˆจแ‰ตแŠ“ แˆแˆณแˆŒ แˆ˜แ‹ฐแ‰ฅ` 3. `แ‹“ . แˆ . แ‰ แŠ‹แˆ‹ แˆˆแˆ†แŠ‘แ‰ต แ‹“แˆ˜แ‰ณแ‰ต แŒแŠ• แ‰ แˆŒแˆ‹ แ‰€แŠ• แˆ‹แ‹ญ แˆ˜แˆ†แŠ‘แŠ• แ‹ญแŒˆแŠ•แ‹˜แ‰ก แข แˆˆแŠฅแАแ‹šแ‹ซ แ‹“แˆ˜แ‰ถแ‰ฝ แ‹ญแˆ… แ‹จแ‰€แŠ•` **Context Size 4:** 1. `แ‹จแŠ แˆ›แˆญแŠ› แˆแˆณแˆŒ แАแ‹ แข แ‰ตแˆญแŒ‰แˆ™ แˆ˜แ‹ฐแ‰ฅ : แ‹ซแˆแ‰ฐแ‰ฐแˆจแŒŽแˆ˜ แˆแˆณแˆŒ แˆ˜แ‹ฐแ‰ฅ : แ‰ฐแˆจแ‰ตแŠ“ แˆแˆณแˆŒ แˆ˜แ‹ฐแ‰ฅ : แ‰ฐแˆจแ‰ตแŠ“ แˆแˆณแˆŒ แˆ˜แ‹ฐแ‰ฅ :` 2. `แ‹“ . แˆ . แŠ แˆตแ‰€แ‹ตแˆž แ‹ˆแ‹ญแˆ แŠจ2091 แ‹“ . แˆ . แ‰ฐแŠญแˆˆแŒปแ‹ตแ‰… แˆ˜แŠฉแˆชแ‹ซ แˆ˜แ‹ฐแ‰ฅ : แ‰ฐแŠญแˆˆแŒปแ‹ตแ‰… แˆ˜แŠฉแˆญแ‹ซ แˆ˜แ‹ฐแ‰ฅ :` 3. `แŠฅ . แŠค . แŠ  . แ‰  1914 แ‹จแˆฉแˆฒแ‹ซ แŠ•แŒ‰แˆ  แАแŒˆแˆฅแ‰ต แŠ’แŠฎแˆ‹แˆต ii ( 1894 - 1917 ) แŠฅ` ### Key Findings - **Best Predictability:** Context-4 with 97.4% predictability - **Branching Factor:** Decreases with context size (more deterministic) - **Memory Trade-off:** Larger contexts require more storage (1,342,049 contexts) - **Recommendation:** Context-3 or Context-4 for text generation --- ## 4. Vocabulary Analysis ![Zipf's Law](visualizations/zipf_law.png) ![Top Words](visualizations/top20_words.png) ![Coverage Curve](visualizations/vocab_coverage.png) ### Statistics | Metric | Value | |--------|-------| | Vocabulary Size | 108,024 | | Total Tokens | 1,810,273 | | Mean Frequency | 16.76 | | Median Frequency | 3 | | Frequency Std Dev | 184.67 | ### Most Common Words | Rank | Word | Frequency | |------|------|-----------| | 1 | แАแ‹ | 28,114 | | 2 | แŠฅแŠ“ | 23,158 | | 3 | แˆ˜แ‹ฐแ‰ฅ | 19,525 | | 4 | แˆ‹แ‹ญ | 13,580 | | 5 | แˆแˆณแˆŒ | 12,239 | | 6 | แ‹แˆตแŒฅ | 9,959 | | 7 | แАแ‰ แˆญ | 9,632 | | 8 | แ‹ˆแ‹ฐ | 9,166 | | 9 | แˆ | 8,691 | | 10 | แ‹“ | 8,629 | ### Least Common Words (from vocabulary) | Rank | Word | Frequency | |------|------|-----------| | 1 | แŒ‚แŠ’แŠซ | 2 | | 2 | แ‹ฒแŠ’แŠซแˆ‹ | 2 | | 3 | แ‹ˆแˆตแ‹ฐแˆฝ | 2 | | 4 | แŠ แŠ•แŠณแŠณ | 2 | | 5 | แˆ˜แ‹ณแˆแ‹ˆ | 2 | | 6 | แˆจแ‹ตแŠฅ | 2 | | 7 | แŠ แŠ•แ‹ฐแŠ›แ‹ญแ‰ฑ | 2 | | 8 | แ‹ˆแ‹ฐแˆฐแˆแ | 2 | | 9 | แ‹จแŠ’แŠฎแ–แˆŠแˆต | 2 | | 10 | แŒ‚แˆแŠ“แ‹šแ‹จแˆ | 2 | ### Zipf's Law Analysis | Metric | Value | |--------|-------| | Zipf Coefficient | 0.9297 | | Rยฒ (Goodness of Fit) | 0.994674 | | Adherence Quality | **excellent** | ### Coverage Analysis | Top N Words | Coverage | |-------------|----------| | Top 100 | 22.3% | | Top 1,000 | 44.9% | | Top 5,000 | 65.4% | | Top 10,000 | 74.1% | ### Key Findings - **Zipf Compliance:** Rยฒ=0.9947 indicates excellent adherence to Zipf's law - **High Frequency Dominance:** Top 100 words cover 22.3% of corpus - **Long Tail:** 98,024 words needed for remaining 25.9% coverage --- ## 5. Word Embeddings Evaluation ![Embedding Isotropy](visualizations/embedding_isotropy.png) ![Similarity Matrix](visualizations/embedding_similarity.png) ![t-SNE Words](visualizations/tsne_words.png) ![t-SNE Sentences](visualizations/tsne_sentences.png) ### Model Comparison | Model | Vocab Size | Dimension | Avg Norm | Std Norm | Isotropy | |-------|------------|-----------|----------|----------|----------| | **mono_32d** | 40,456 | 32 | 3.565 | 0.969 | 0.8976 | | **mono_64d** | 40,456 | 64 | 4.280 | 0.895 | 0.9070 ๐Ÿ† | | **mono_128d** | 40,456 | 128 | 5.026 | 0.790 | 0.8490 | | **embeddings_enhanced** | 0 | 0 | 0.000 | 0.000 | 0.0000 | ### Key Findings - **Best Isotropy:** mono_64d with 0.9070 (more uniform distribution) - **Dimension Trade-off:** Higher dimensions capture more semantics but reduce isotropy - **Vocabulary Coverage:** All models cover 40,456 words - **Recommendation:** 100d for balanced semantic capture and efficiency --- ## 6. Summary & Recommendations ![Performance Dashboard](visualizations/performance_dashboard.png) ### Production Recommendations | Component | Recommended | Rationale | |-----------|-------------|-----------| | Tokenizer | **32k BPE** | Best compression (3.28x) with low UNK rate | | N-gram | **5-gram** | Lowest perplexity (2,321) | | Markov | **Context-4** | Highest predictability (97.4%) | | 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) ร— 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. **Rยฒ (Coefficient of Determination)** > *Definition:* Measures how well the linear fit explains the frequency-rank relationship. Ranges from 0 to 1. > > *Intuition:* Rยฒ near 1.0 means the data closely follows Zipf's law; lower values indicate deviation from expected word frequency patterns. > > *What to seek:* Rยฒ > 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 1. **Compare within model families:** Metrics are most meaningful when comparing models of the same type (e.g., 8k vs 64k tokenizer). 2. **Consider trade-offs:** Better performance on one metric often comes at the cost of another (e.g., compression vs. OOV rate). 3. **Context matters:** Optimal values depend on downstream tasks. Text generation may prioritize different metrics than classification. 4. **Corpus influence:** All metrics are influenced by corpus characteristics. Wikipedia text differs from social media or literature. 5. **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](https://huggingface.co/datasets/omarkamali/wikipedia-monthly) - a monthly snapshot of Wikipedia articles across 300+ languages. ### Project A project by **[Wikilangs](https://wikilangs.org)** - Open-source NLP models for every Wikipedia language. ### Maintainer [Omar Kamali](https://omarkamali.com) - [Omneity Labs](https://omneitylabs.com) ### Citation If you use these models in your research, please cite: ```bibtex @misc{wikilangs2025, author = {Kamali, Omar}, title = {Wikilangs: Open NLP Models for Wikipedia Languages}, year = {2025}, publisher = {HuggingFace}, url = {https://huggingface.co/wikilangs} institution = {Omneity Labs} } ``` ### License MIT License - Free for academic and commercial use. ### Links - ๐ŸŒ Website: [wikilangs.org](https://wikilangs.org) - ๐Ÿค— Models: [huggingface.co/wikilangs](https://huggingface.co/wikilangs) - ๐Ÿ“Š Data: [wikipedia-monthly](https://huggingface.co/datasets/omarkamali/wikipedia-monthly) - ๐Ÿ‘ค Author: [Omar Kamali](https://huggingface.co/omarkamali) --- *Generated by Wikilangs Models Pipeline* *Report Date: 2025-12-27 05:42:07*