Recognizing 95% of the words in English YouTube videos takes the 3,814 most frequent words; in Japanese videos it takes 8,651. The top 1,000 words alone cover 86% of English and 78% of Japanese.
Key findings
- English: the 3,814 most frequent words cover 95% of all words heard; 8,443 cover 98%.
- Japanese: the 8,651 most frequent words cover 95%; 17,629 cover 98%.
- Top 1,000 words: 86% of English and 78% of Japanese words heard.
- Japanese N2 and N1 videos need about 12,301–12,678 words for 95%, against 6,712 for N4.
How much the most frequent words cover
Research on reading and listening often cites 95% known words as the point where real content becomes followable and 98% as comfortable. The table shows how much of everything said in the videos the most frequent words cover.
The first few hundred words do most of the work, and each step after that buys less: the last few percent are spread over thousands of words that each appear only a handful of times.
| Most frequent words | Japanese | English |
|---|---|---|
| 100 | 52.7% | 57.6% |
| 250 | 63.4% | 70.6% |
| 500 | 71.0% | 78.6% |
| 1,000 | 78.0% | 85.5% |
| 2,000 | 84.5% | 91.2% |
| 3,000 | 87.9% | 93.7% |
| 5,000 | 91.7% | 96.2% |
| 10,000 | 95.7% | 98.4% |
Japanese: words needed by JLPT level
N5 to N3 videos sit close together; N2 and N1 videos need roughly 1.6 to 1.8 times as many words for the same coverage. Most N2 and N1 videos here are TV news, which draws on a far wider vocabulary than vlogs and learner channels.
| Level | Videos | Words for 90% | Words for 95% | Words for 98% |
|---|---|---|---|---|
| N5 | 257 | 3,408 | 7,489 | 14,973 |
| N4 | 452 | 2,899 | 6,712 | 14,399 |
| N3 | 770 | 3,341 | 7,733 | 16,405 |
| N2 | 795 | 6,122 | 12,301 | 22,256 |
| N1 | 244 | 6,446 | 12,678 | 23,541 |
| All levels | 2518 | 3,923 | 8,651 | 17,629 |
English: words needed by CEFR level
A2 videos are the easiest to cover. A1 videos need more words than A2: many are children's shows and stories, which bring in animals, objects and sounds that everyday talk rarely uses. From B1 the requirement grows with each level. For how to use these thresholds when choosing what to watch, see comprehensible input for English listening.
| Level | Videos | Words for 90% | Words for 95% | Words for 98% |
|---|---|---|---|---|
| A1 | 225 | 1,598 | 3,335 | 7,077 |
| A2 | 530 | 1,184 | 2,466 | 5,491 |
| B1 | 778 | 1,537 | 3,468 | 7,791 |
| B2 | 502 | 2,068 | 4,665 | 10,102 |
| C1 | 105 | 2,771 | 5,719 | 11,789 |
| All levels | 2146 | 1,705 | 3,814 | 8,443 |
Method
- Corpus: 2,518 Japanese videos (2,110,066 words, 233 hours of speech) and 2,146 English videos (2,447,824 words, 229 hours of speech) from YouTube creators, as processed by LingoDew up to 2026-10-16. Distinct words: 42,840 Japanese and 29,636 English.
- Every word in the subtitles is linked to a dictionary entry, so inflected forms of the same entry count as one word. Names, numbers and interjections count like any other word.
- Words are ranked by how often they occur in all videos of that language; coverage at N is the share of all words spoken in a level's videos that belong to the top N. Because the ranking comes from the same videos, these numbers are a best case for this kind of content; a learner whose vocabulary comes from textbooks will need somewhat more.
- Japanese is split into words the way dictionaries list them, so particles (は, を) and endings (ます) are separate words. That makes Japanese and English counts comparable in spirit but not one-to-one.
- Levels are the difficulty labels LingoDew shows on every video (JLPT N5–N1 for Japanese, CEFR A1–C2 for English). They are estimated from vocabulary, grammar and speed, and some are reviewed by hand. Levels with fewer than 20 videos are left out.
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