Luckily for Ellet, his students have plenty of motivation to improve. "Recruiters and companies are saying, 'Send us a writing sample, and if you don't meet our standards for communication, we are not hiring you,'" he said.
(Read more: Employers: 'Skills gap' is not our problem to fix)
It's not just anecdotal: In a 2011 survey of corporate recruiters by the Graduate Management Admission Council, the organization that administers the standardized test for business school, 86 percent said strong communication skills were a priority—well ahead of the next skill. (Oddly, though, when recruiters were asked in a separate question what changes business schools should make to meet employers' needs, the recruiters overwhelmingly called for something different: practical experience.)
(Read more: HR staffs, recruiters overlook qualified job seekers)
The good news for job seekers is that some companies are providing help with writing. Lowsky estimates that Right Management is seeing an increase of 20 to 25 percent in the number of clients investing in career development for employees, including improving their communication skills.
T. Rowe Price has been working independently on employees' communication skills for some time. With offices in multiple time zones and time sensitive investment decisions to make, the firm's leaders understand that clear communications are essential. A number of senior people at the firm may work with analysts and portfolio managers on their communications, but Garry Cosnett, head of global equity communications, does it full time.
Cosnett spends considerable time with newly hired analysts, helping them learn to organize their writing and make it clear and persuasive. Another part of his job is to read writing samples from prospective hires, often second year MBA candidates. "Sometimes we ask for writing samples even prior to the interview process, and I will take a look at that," he said. "I've been doing this for so long, I have a pretty good sense of what's fixable and what's terminal."
T. Rowe Price tends to hire graduates of the most selective business schools, along with some lateral hires from other firms – but even for this elite group, writing can be a challenge, Cosnett says.
"It's amazing, the frequent disconnect," he said. "These are people who all did the very best at the best schools, probably since preschool, but they really have not developed their writing skills to the degree that they would have to to succeed in this organization."
Some new hires are skeptical, he said. "People think when they first meet me that I'm going to grill them on semicolons." But in fact, he says, he is teaching them what they need in order to succeed at the firm. "You can be the smartest person here, but if you can't convince the portfolio managers to buy what you're selling, you won't be successful." (In Wall Street terms, that means you won't make much money.)
"So much," he said, "is driven by the written word."