Pearson's tau for top-ten languages

     en    es    ru    ja    de    fr    pt    it    pl    zh
----------------------------------------------------------------
en | 1.000 0.313 0.207 0.263 0.334 0.294 0.305 0.287 0.315 0.286
es | 0.313 1.000 0.423 0.412 0.555 0.584 0.668 0.598 0.564 0.471
ru | 0.207 0.423 1.000 0.332 0.425 0.408 0.410 0.426 0.439 0.372
ja | 0.263 0.412 0.332 1.000 0.529 0.470 0.412 0.479 0.486 0.532
de | 0.334 0.555 0.425 0.529 1.000 0.613 0.551 0.639 0.642 0.504
fr | 0.294 0.584 0.408 0.470 0.613 1.000 0.563 0.633 0.588 0.464
pt | 0.305 0.668 0.410 0.412 0.551 0.563 1.000 0.585 0.556 0.439
it | 0.287 0.598 0.426 0.479 0.639 0.633 0.585 1.000 0.608 0.484
pl | 0.315 0.564 0.439 0.486 0.642 0.588 0.556 0.608 1.000 0.488
zh | 0.286 0.471 0.372 0.532 0.504 0.464 0.439 0.484 0.488 1.000

Pearson's Tau value between language pairs.
There are 1536 articles that exist in all of the top 10 languages
The rankings of these articles are the basis for computation

Observe the matrix is symmetric and there is perfect correlation
along the matrix identity.

Highest correlation = 0.668 (Portuguese and Spanish; logical)
Lowest correlation  = 0.207 (English and Russian)