Business is indeed global these days. For many professionals that means investing the time and the money to learn a foreign language could pay off in terms of career advancement and salary.

Especially in jobs in finance and sales, learning languages -- such as Mandarin, Arabic and Japanese -- could make sense. Workers who depend on commissions or are looking to introduce products overseas could also benefit, experts say.

But bilingualism doesn't come cheap. You can spend anywhere from $1,500 to $3,000 or more for classes that will give you proficiency in a second language.

"There's a growing awareness that studying a foreign language can help one obtain a really successful career and make [you] a lot more hirable," says Jerry Lampe, deputy director of the National Foreign Language Center.

Second languages, especially Spanish in the U.S., are likely to help in fields where you deal directly with buyers, such as in automobile sales.

Call centers for collection agencies will pay a 10% to 15% premium to bilingual workers of their experience and skill, says Kurt Ronn, founder of professional-level recruitment firm HRworks.

Premium Pay

"They're paying a premium not because Spanish is more important. It's just a segment of the market where they have trouble finding people who are truly bilingual," Mr. Ronn says.

Those who speak only English can get by in the business world. But if you're going to study another language, some may be more helpful to your career than others, says Paul Platten, global-practice director of the human capital group at Watson Wyatt Worldwide.

Mandarin can be particularly useful, especially in fields such as manufacturing, he says.

"People with Chinese language skills are very much in demand. I think that definitely becomes in your favor when you're negotiating salary increases," Mr. Platten says. "I don't think most companies would pay for most of the European languages -- English is just too common over there."

He adds that financial-services professionals could benefit from learning another language. "There's a lot of deal making around the world," he notes.

Service-Sector Value

Language skills can also be key for service industries. At the Willard InterContinental Washington, a luxury hotel a few blocks from the White House, a staff of about 570 from 42 nations speaks 19 languages.

Bilingualism is not an absolute requirement, but it is desirable, according to Wendi Colby, director of human resources.

Workers with skills in a second language may have an edge when it comes to climbing Willard's professional ladder.

"The individual that spoke more languages would have a better chance for a managerial role, whatever the next level would be," Ms. Colby says. "They are able to deal with a wide array of clients, employees."

The hotel offers foreign-language classes to employees at no charge as part of their training and development through the International Center for Language Studies.

In the past three years, 35 Willard employees have studied a foreign language, with another 25 studying English.

"It's to help them in their job," Ms. Colby says. "It's a great opportunity because once they go back to work the next day they can practice that language."

Pricey Classes

Unless your company funds your instruction, picking up a language could be financially daunting. A 10-week group class for two to four students costs about $1,500 at Berlitz, an international provider of language instruction. Its online instruction costs about the same.

The Boston Language Institute charges $499 for each level -- it provides five levels of instruction plus a conversational class -- for its eight-week group Mandarin classes. Arabic will set you back $599 a level.

The Boston institute has about 3,000 students a year studying from 30 to 40 languages, and in some cases it goes to companies to teach.

The eight most popular classes are in Spanish, Japanese, Italian, French, Portuguese, Arabic, Mandarin and Russian.

"In most cases people come here on their own volition...sometimes reimbursed by their companies, sometimes not," says Siri Karm Singh Khalsa, president of the institute.

Some of the school's clients are workers with companies that do business in South America, Europe or Asia. Many students studying English are engineers or research scientists.

"They're at a point where they've received a high enough level of seniority that their company is willing to invest in them," Mr. Khalsa says.