Top 9 language families on Wikipedia by number of articles (January 2009)

These are the top 9 language families on Wikipedia at the moment, obtained from this page. The chart shows the area each language takes up of the top nine, not Wikipedia as a whole. The rest of the languages put together make up a bit over a million articles, so about twice the size of the green area that represents Japanese. Note that Turkic languages are placed above Semitic languages for some reason even though the latter has slightly more, but this makes no visible difference in the chart so I just kept the same order.

• 1 Germanic languages (4,666,717 – 26 – 23 – 55.89%)
• 2 Romance languages (2,540,230 – 30 – 26 – 28.38%)
• 3 Slavonic languages (1,618,000 – 19 – 17 – 34.73%)
• 4 Japonic languages (535,185 – 1 – 1 – 100%)
• 5 Constructed languages (289,220 – 8 – 7 – 40.64%)
• 6 Finno-Permic languages (246,364 – 8 – 4 – 74.74%)
• 7 Sinitic languages (230,260 – 8 – 6 – 91.41%)
• 8 Turkic languages (169,452 – 13 – 7 – 71.92%)
• 9 Semitic languages (172,166 – 6 - 4 - 49.01%)

Constructed languages is also a bit skewed thanks to Simple English being included in the list, plus a bot that Volapük used:

1. Volapük – vo – 117,529 articles
2. Esperanto – eo – 106,507 articles
3. Simple English – simple – 40,347 articles
4. Ido – io – 16,124 articles
5. Interlingua – ia – 4,370 articles
6. Novial – nov – 2,495 articles
7. Interlingue (Occidental) – ie – 1,156 articles
8. Lojban – jbo – 692 articles

in terms of actual users it's nowhere near the big three (Esperanto, then Ido and Interlingua / or Interlingua and Ido), or even others such as Occidental and Lojban. In fact, Lingua Franca Nova has more real activity (by which I mean actual conversation in the language) even though it still hasn't been approved for its own Wikipedia.