A cross-linguistic comparison between the four patient groups. Left figure (mean number of errors on the affirmative sentences): the four patient groups do not differ significantly from each other. Mann-Whitney U-tests were used for comparison. (Dutch–Norwegian: z = −0.39; p = 0.695, Dutch–English: z = −1.52, p = 0.127, Norwegian–English: z = −1.00; p = 1.0, Norwegian–Spanish: z = −0.11; p = 0.912, English–Spanish: z = −1.33; p = 0.182). Right figure (mean number of errors on the negative sentences): the Dutch and Norwegian (z = −0.39; p = 0.695) and the Spanish and English (z = −1.09; p = 0.276) results are comparable The English and Spanish perform significantly worse than the Dutch and Norwegian patients (English–Dutch: z = −2.84; p = 0.005, English–Norwegian: z = −2.47; p 0.0013, Spanish–Dutch: z = −2.22; p = 0.027 and Spanish–Norwegian: z = −2.16; p = 0.031.