Language:
Specialization and specialisation are both English terms.
Specialized and specialised are both English terms.
Usage:
Specialization is predominantly used in American (US) English (en-US) while specialisation is predominantly used in British English (used in UK/AU/NZ) (en-GB).
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Issue 1: "specialization" should be changed into "specialisation"
Issue 2: "specialized" should be changed into "specialised"
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Currently on the website both terms ("specialized" and "specialised") are used and is not consistent.
https://www.rkconsult.nl/
https://www.rkconsult.nl/
https://www.rkconsult.nl/front-slider/sl...lmovement/
https://www.rkconsult.nl/front-slider/slideonland/