If proving competency in Spanish language is a requirement, you can take a test to obtain one of the following certificates:

Diplomas de Español como Lengua Extranjera (DELE)
The DELEs issued by Spain’s Ministry of Education, offer official accreditation of mastery of the Spanish language for citizens of countries in which Spanish is not the official language. The examinations, offered at three levels, test the student ability to read, write, speak and understand Spanish.

The Chamber of Commerce of Madrid Examinations
Founded in 1887, the Madrid Chamber of Commerce and Industry is a Public Corporation, a consultative and collaborative body liaising with the Administrations, which represents, promotes and defends the general interests of companies in the region. It offers accreditaion of mastery of the Spanish for Business environment, through three official tests.

The following institutions offer test preparation courses to get the certificates mentioned above

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