Question

why did the Britisph preserve the official language

Answer 1

Answer:

because by these official languages they know what had done in the past

Answer 2

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British had preserved official documents, because they thought if they write and record everything, it will later be easier for them to study them and debate. They kept official records of what they thought was right, so that in the future, those records can serve as proofs of all the decisions that they had taken.