At first sight, it might appear pointless for a native English speaker well into their career to go to the trouble of learning a foreign language.
Everyone accepts that English is the lingua franca of the banking world and 90% of cross-border transactions are negotiated in English. Even the boards of top multinationals now conduct their business in English.
Yet some business schools, acting on feedback from recruiters, actively require their students to graduate in a second language.
Says Gareth Howells, senior MBA programme manager at the London Business School: "We require all our MBA students to graduate in a language other than English. It increases their internationalism and their marketability and it's what employers say they want."
If your career path leads you to work for a foreign-owned bank, there's an obvious advantage in learning your employer's language: much of the paperwork emanating from head office won't be in English.
Also, internal communication and relationships, as well as career progression, can be much smoother if you speak the language.
Grahame Cook, head of equity capital markets at WestLB Panmure, speaks from experience: "The bank produces a lot of data, memos and the like, in German. Any manager who has documents pass across his desk may be unable to do his job properly if he can't read them."
Cook has been learning German for a year, and is doing well. Twice a week he takes a two-hour one-to-one lesson in his lunch break at a language school in Düsseldorf.
Apart from foreign-owned banks, Sally Rowley-Williams, head of the UK financial services practice at executive search consultants Korn Ferry, identifies particular areas where languages are more important.
These include asset management, M&A, venture capital and private equity, where a lot of work takes place around Europe. She describes an ability to speak another language as "more than a nice-to-have, but not usually a requirement".
"The ability to complete an M&A deal is a lot more important than the ability to speak a foreign language. On the other hand, if a recruiter had the choice between two otherwise equally qualified people the job would almost certainly go to the one with another language."
According to Morgan Stanley Dean Witter: "The benefits of employees being able to converse in our clients' native languages are gaining importance. We now have more people than ever before attending language classes."
Currently, more than 450 people at MSDW in London are learning 11 languages, among which German, Italian and Spanish are particularly popular.
Amanda Whiteford, head of training at Dresdner Kleinwort Benson, which supports language learning at all levels, says DrKB believes in a "holistic" approach to language learning.
This sees advantage not just in knowing a language but "understanding the culture and customs of the people you are dealing with".
"There is less room for misunderstanding if you know why and how people approach business deals," she says.
Currently 125 people are learning nine languages (principally German, French and English, plus Italian and Spanish).
Although there is no general requirement to be fluent in a second language at DrKB, Whiteford accepts that in many jobs it is "highly desirable, a distinct advantage".
Clearly some roles require a level of capability that can only be provided by a native speaker in whatever language.
A deal with the Japanese may best be conducted by a Japanese speaker, not just because the language is highly complex for a foreigner to learn, but also because of their innate understanding of Japanese ways of doing business.
But you shouldn't underestimate the value of being able to show that you have taken the time and the trouble to learn a language.
Says Cook of WestLB Panmure: "Investment banking is a people business. It is about winning business by convincing people that they can put their trust in you.
"Many potential clients of investment banks are still very domestic to their own country. They feel more comfortable talking to a native, or at least to someone speaking their own language and familiar with that culture.
"Being seen to be making that effort helps engender trust," says Cook.
Virginia Withers of language specialists Linguarama makes the point that even if English is the language used for meetings and negotiations, an English person's standing is enhanced if they can speak the language.
"The higher up an organisation you go, the more you get involved in socialising with clients. And if you can't function in social situations abroad you become very dependent on your host," she says.
Laurent Demeeus, a consultant in the financial services practice of executive search consultants Egon Zehnder, sums it up: "You can definitely have a successful career in investment banking without speaking anything but English. But having another language can help a lot along the way."