Language of money (7)

I believe the answer is:

guarani

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This might be a double definition.

'language' is the first definition.
(Guarani is an example)

'money' is the second definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.

'of' acts as a link.

Can you help me to learn more?

(Other definitions for guarani that I've seen before include "South American Indian language" , "S. Am. Indian people" .)

I've seen this clue in The Hindu.

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