How are language skills important to delegate effectively; specially when proposing an offer in marketing or sales fields?

Language fluency is the most essential part of Sales and Marketing. If you don't explain and illustrate about the product how are you going to sell?

Languages portray a great deal of professionalism in today business world.

Of Course language skills is important , but It depends on type of customer and the nature of industry as well. If your customers are traders or distributors, may they will be offended when offering them proposals in a foreign language. If your customer is A class or has a high level of education, then your language skills will present your quality.So you have to be careful regarding this point.