Why would a single language and a single currency be such an advantage to a trader?

Answer 1

Having a single language creates for significant ease in the creation of contracts, negotiation of cultures, and customs and declaration for international movement. These all make merchantry easier.

Having a single currency allows for stability in smaller states and allows for the combined wealth of a variety of states to make a currency stronger. Additionally a merchant would not have to exchange currencies when leaving and departing countries, limiting costs of exchange. This would also minimize price fluctuations, rises and falls in insurance and interest rates, and provide for a generally more stable economic environment.

Answer 2

A single language allows for clear communication with trading partners, reducing misunderstandings and errors. A single currency eliminates currency exchange costs and fluctuations, making transactions more predictable and efficient. Both factors facilitate smoother trade negotiations and transactions.